JP4671562B2 - Illumination device and liquid crystal display device - Google Patents

Description

【００４３】
ここで、ｎは、ｎ番目の光反射部に関するものであることを意味する。また、Ｘ（ｎ）は、線状導光体１４の端面からｎ番目の光反射部までの距離である。また、θ_OUT（ｎ）は、ｎ番目の光反射部により反射された光の出射角である。
【００４４】
式（１）を変形すると、光反射部２０ａの面の傾斜角θ（ｎ）は、以下のような式で表される。
【００４５】
【数２】

【００４６】
光反射部２０ｂについては、ＬＥＤ１２ａから直接光反射部２０ｂに入射される光が、光反射部２０ｂの面で全反射されて、線状導光体１４の出射側から出射位置に応じた出射角θ_OUT（ｎ）で出射されるように、光反射部２０ｂの面の傾斜角θ（ｎ）を設定する。
【００４７】
この場合には、以下のような式が成立する。
【００４８】
【数３】

【００４９】
式（３）を変形すると、光反射部２０ｂの面の傾斜角θ（ｎ）は、以下のような式で表される。
【００５０】
【数４】

【００５１】
なお、図２（ｂ）に示すように、光反射部の紙面左側の面の傾斜角θ_L（ｎ）については、紙面左側に設けられたＬＥＤ１２ａから導入される光が所望の出射角θ_OUT（ｎ）で出射されるように設定する。一方、光反射部の紙面右側の面の傾斜角θ_R（ｎ）については、紙面右側に設けられたＬＥＤ１２ｂから導入される光が所望の出射角θ_OUT（ｎ）で出射されるように設定する。
【００５２】
また、厳密には、図４に示すように、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬが０ｍｍでない場合には、空気中の屈折率Ｎ_aと線状導光体の屈折率Ｎ_gとで屈折率が異なるため、光路のずれが生じる。しかし、かかる要因による光路のずれは、光反射部２０の面の傾斜角θ（ｎ）を求める上では、無視することが可能なものである。このため、ここでは、計算式を簡単にすべく、かかる要因の影響については無視して計算式を立てている。
【００５３】
また、厳密には、図４に示すように、光はＬＥＤ１２ａ、１２ｂの中心近傍から面状に出射される。しかし、光反射部２０の面の傾斜角θ（ｎ）を求める上では、ＬＥＤ１２ａ、１２ｂの中心点から光が出射されるものとして計算式を立てても、誤差は無視し得る程小さい。このため、ここでは、計算式を簡単にすべく、ＬＥＤ１２ａ、１２ｂの中心点から光が出射されるものとして、計算式を立てている。
【００５４】
次に、本実施形態の光反射部２０の面の傾斜角θ（ｎ）の具体的な設定値の例について図５を用いて説明する。図５は、上記の式に基づいて求められた光反射部の面の傾斜角θ（ｎ）の例を示すグラフである。横軸は、線状導光体１４の端面から光反射部２０までの距離Ｘ（ｎ）を示しており、縦軸は、光反射部２０の面の傾斜角θ（ｎ）を示している。
【００５５】
ここでは、画面サイズを２インチ、表示画面の幅を３５ｍｍ、光反射部２０の数を１５０個、光反射部２０のピッチを０．２３ｍｍ、線状導光体１４の厚さｔを３ｍｍ、線状導光体１４の長さＬを３７ｍｍ、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬを０ｍｍ、線状導光体１４の屈折率を１．５１、視認する人間の目と表示画面との距離を３５０ｍｍとして計算した。
【００５６】
光反射部２０の面の傾斜角θ（ｎ）を図５のように設定すると、図６のような光強度分布が得られる。図６は、本実施形態による照明装置の光強度分布を示すグラフである。横軸は、線状導光体における位置を示しており、縦軸は、光強度を示している。ここでは、線状導光体１４の中心から出射される光については０度の光が目に到達し、線状導光体１４の端部から出射される光については±２．８度の光が目に到達するものとして、実際に人間の目に到達し得る光の強度分布が求められている。
【００５７】
図６から分かるように、本実施形態による照明装置では、ほぼ均一な光強度分布が得られている。
【００５８】
このように本実施形態による照明装置は、線状導光体１４から出射される光の出射位置に応じて、所望の出射角θ_ＯＵＴ（ｎ）で光が出射されるように、光反射部２０の面の傾斜角θ（ｎ）が設定されていることに主な特徴がある。
【００５９】
図２９に示す提案されている照明装置では、光反射部の面がいずれも等しい傾斜角α（図３１参照）に設定されていたため、出射位置に応じて所望の出射角で光を出射することはできなかった。このため、提案されている照明装置では、視認する人間の目に到達し得る光の強度分布を、均一化することができなかった。
【００６０】
これに対し、本実施形態では、線状導光体１４から出射される光の出射位置に応じて、所望の出射角θ_ＯＵＴ（ｎ）で光が出射されるように、光反射部２０の面の傾斜角θ（ｎ）が設定されているため、視認する人間の目に光を収束することができる。このため本実施形態によれば、人間の目に到達し得る光の強度分布を均一化することができる。従って、本実施形態によれば、良好な表示特性を実現することができる。
【００６１】
［第２実施形態］
本発明の第２実施形態による照明装置を図７乃至図９を用いて説明する。図７は、本実施形態による照明装置を示す平面図である。図８は、人間の目と表示画面との関係を示す概念図である。図９は、本実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。図１乃至図６に示す第１実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【００６２】
本実施形態による照明装置は、線状導光体１４から出射される光の出射角θ_OUT（ｎ）を０度、即ち、線状導光体１４の長手方向に対して垂直な方向に光が出射されるように、光反射部２０の面の傾斜角θ（ｎ）がそれぞれ設定されていることに主な特徴がある。
【００６３】
第１実施形態による照明装置では、出射位置に応じて、出射角θ_OUT（ｎ）が所望の角度となるように、光反射部２０の面の傾斜角θ（ｎ）をそれぞれ設定していたが、表示画面を視認する人間の目の位置は、必ずしも面状導光体１６の法線方向と一致するとは限らない。一方、出射角θ_OUT（ｎ）を一律に０度に設定したとしても、表示画面から３５０ｍｍ離間した人間の目に達するまでに、光はある程度広がるため、実際には、第１実施形態と同様の光強度分布が得られる。また、出射角θ_OUT（ｎ）を一律に設定すれば、光反射部２０の面の傾斜角θ（ｎ）を求める際の計算を容易化し得る。
【００６４】
そこで、本実施形態では、出射角θ_OUT（ｎ）を一律に０度に設定している。
【００６５】
本実施形態では出射角θ_OUT（ｎ）を０度に設定するため、式（２）、式（４）にθ_OUT（ｎ）＝０度を代入すればよい。
【００６６】
式（２）にθ_OUT（ｎ）＝０度を代入すると、光反射部２０ａの面の傾斜角θ（ｎ）は、以下のような式で表される。
【００６７】
【数５】

【００６８】
また、式（４）にθ_OUT（ｎ）＝０度を代入すると、光反射部２０ｂの面の傾斜角θ（ｎ）は、以下のような式で表される。
【００６９】
【数６】

【００７０】
次に、本実施形態による照明装置の光反射部の面の傾斜角θ（ｎ）の設定値の例について図９を用いて説明する。図９は、上記の式に基づいて求められた光反射部の面の傾斜角θ（ｎ）の例を示すグラフである。横軸は、線状導光体１４の端面から光反射部２０ａ、２０ｂまでの距離を示しており、縦軸は、光反射部２０ａ、２０ｂの面の傾斜角θ（ｎ）を示している。
【００７１】
なお、本実施形態でも、第１実施形態と同様に、画面サイズを２インチ、表示画面の幅を３５ｍｍ、光反射部２０の数を１５０個、光反射部２０のピッチを０．２３ｍｍ、線状導光体１４の厚さｔを３ｍｍ、線状導光体１４の長さＬを３７ｍｍ、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬを０ｍｍ、線状導光体１４の屈折率を１．５１、視認する人間の目と表示画面との距離を３５０ｍｍとして計算した。
【００７２】
光反射部２０ａ、２０ｂの面の傾斜角θ（ｎ）を図９のように設定すると、線状導光体１４から出射される光の出射角θ_OUT（ｎ）はいずれも０度となり、第１実施形態とほぼ同様に均一な光強度分布が得られる。従って、本実施形態によれば、第１実施形態と同様に、良好な表示特性を実現することができる。
【００７３】
［第３実施形態］
本発明の第３実施形態による照明装置を図１０及び図１１を用いて説明する。図１０は、本実施形態による照明装置を示す平面図である。図１１は、本実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。図１乃至図９に示す第１又は第２実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【００７４】
本実施形態による照明装置は、いずれの光反射部２０ｃについても、ＬＥＤ１２ａ、１２ｂから直接光反射部２０ｃに入射される光が、光反射部２０ｃで全反射されて、線状導光体１４の出射側から出射されるように、光反射部２０ｃの面の傾斜角θ（ｎ）が設定されていることに主な特徴がある。
【００７５】
第１及び第２実施形態による照明装置では、線状導光体１４の出射側の面で全反射された光を更に全反射するように傾斜角θ（ｎ）が設定された光反射部２０ａと、ＬＥＤ１２ａ、１２ｂから直接入射される光を全反射するように傾斜角θ（ｎ）が設定された光反射部２０ｂとが混在していた。
【００７６】
これに対し、本実施形態では、図１０に示すように、いずれの光反射部２０ｃについても、ＬＥＤ１２ａ、１２ｂから直接入射される光を全反射するように、光反射部２０ｃの面の傾斜角θ（ｎ）が設定されている。なお、光反射部２０ｃは、線状導光体１４の反射側に多数形成されているが、図１０では省略されている。
【００７７】
この場合には、光反射部２０ｃの面の傾斜角θ（ｎ）は、上述した式（４）又は式（６）に基づいて設定すればよい。
【００７８】
次に、本実施形態による照明装置の光反射部の面の傾斜角θ（ｎ）の設定値の例について図１１を用いて説明する。図１１は、上記の式に基づいて求められた光反射部の面の傾斜角θ（ｎ）の例を示すグラフである。横軸は、線状導光体１４の端面から光反射部２０ｃまでの距離Ｘ（ｎ）を示しており、縦軸は、光反射部２０ｃの面の傾斜角θ（ｎ）を示している。
【００７９】
なお、本実施形態でも、第１実施形態と同様に、画面サイズを２インチ、表示画面の幅を３５ｍｍ、光反射部２０の数を１５０個、光反射部２０のピッチを０．２３ｍｍ、線状導光体１４の厚さｔを３ｍｍ、線状導光体１４の長さＬを３７ｍｍ、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬを０ｍｍ、線状導光体１４の屈折率を１．５１、視認する人間の目と表示画面との距離を３５０ｍｍとして計算した。
【００８０】
このように光反射部２０ｃの面の傾斜角θ（ｎ）を設定した場合であっても、線状導光体１４から出射される光の出射角θ_OUTはいずれも０度となり、第１及び第２実施形態とほぼ同様に均一な光強度分布が得られる。従って、本実施形態によれば、第１及び第２実施形態と同様に、良好な表示特性を実現することができる。
【００８１】
［第４実施形態］
本発明の第４実施形態による照明装置を図１２乃至図１４を用いて説明する。図１２は、本実施形態による照明装置を示す平面図である。図１３は、本実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。図１４は、本実施形態による照明装置の光強度分布を示すグラフである。図１乃至図１１に示す第１乃至第３実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【００８２】
本実施形態による照明装置は、線状導光体１４が長手方向に複数の領域２２ａ、２２ｂ、２２ｃに区分されており、領域２２ａ、２２ｂ、２２ｃ内にそれぞれ複数形成された光反射部２０ｄ〜２０ｆの面の傾斜角が、区分された領域２２ａ、２２ｂ、２２ｃ内で等しく設定されていることに主な特徴がある。
【００８３】
なお、光反射部２０ｄ〜２０ｆは、線状導光体１４の反射側にそれぞれ多数形成されているが、図１２においては、省略されている。
【００８４】
線状導光体１４の中心を含む領域２２ｃでは、線状導光体１４の中心の位置Ｌ／２を基準として、光反射部２０ｆの面の傾斜角θ₀を設定する。線状導光体１４の出射側の面で全反射された光が、光反射部２０ｆにより全反射されて、線状導光体１４の出射側から出射されるものとして、光反射部２０ｆの面の傾斜角θ₀を設定すると、以下のような式が成立する。
【００８５】
【数７】

【００８６】
式（７）を変形すると、光反射部２０ｆの面の傾斜角θ₀は、以下のような式で表される。
【００８７】
【数８】

【００８８】
また、線状導光体１４の端部の近傍の領域２２ａにおいては、線状導光体１４の端部からの距離がＬ／６の位置を基準として、光反射部２０ｄの面の傾斜角θ′₀を設定する。ＬＥＤ１２ａから直接光反射部２０ｄに入射される光が、光反射部２０ｄで全反射されて、線状導光体１４の出射側から出射されるものとして、光反射部２０ｄの面の傾斜角θ′₀を設定すると、以下のような式が成立する。
【００８９】
【数９】

【００９０】
式（９）を変形すると、光反射部２０ｄの面の傾斜角θ′₀は、以下のような式で表される。
【００９１】
【数１０】

【００９２】
ここで、式（８）と式（１０）とを比較すると、ΔＬの値は極めて小さいため、ΔＬや３・ΔＬは、無視することができ、以下のような式が成立する。
【００９３】
【数１１】

【００９４】
従って、線状導光体１４の端部の近傍の領域２２ａにおいても、式（８）に基づいて、光反射部２０ｄの面の傾斜角をθ₀に設定すればよいこととなる。従って、本実施形態では、線状導光体１４の中心を含む領域２２ｃの光反射部２０ｆの面の傾斜角と、線状導光体１４の端部の近傍の領域２２ａの光反射部２０ｄの面の傾斜角とを、いずれも等しくθ₀に設定すればよい。
【００９５】
また、領域２２ａと領域２２ｃとの間の領域２２ｂにおいては、当該領域２２ｂの中心の位置（Ｘ_C）を基準として、光反射部２０ｅの面の傾斜角θ₁を設定する。ＬＥＤ１２ａから直接光反射部２０ｅに入射される光が、光反射部２０ｅで全反射されて、線状導光体１４の出射側から出射されるものとして、光反射部２０ｅの面の傾斜角θ₁を設定すると、以下のような式が成立する。
【００９６】
【数１２】

【００９７】
式（１２）を変形すると、光反射部２０ｅの面の傾斜角θ₁は、以下のような式で表される。
【００９８】
【数１３】

【００９９】
次に、本実施形態による照明装置の光反射部の面の傾斜角の設定値の例について図１３を用いて説明する。図１３は、上記の式に基づいて求められた光反射部の面の傾斜角θの例を示すグラフである。横軸は、線状導光体の端面から光反射部までの距離Ｘ（ｎ）を示しており、縦軸は、光反射部の面の傾斜角θを示している。
【０１００】
なお、本実施形態でも、第１実施形態と同様に、画面サイズを２インチ、表示画面の幅を３５ｍｍ、光反射部２０の数を１５０個、光反射部２０のピッチを０．２３ｍｍ、線状導光体１４の厚さｔを３ｍｍ、線状導光体１４の長さＬを３７ｍｍ、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬを０ｍｍ、線状導光体１４の屈折率を１．５１、視認する人間の目と表示画面との距離を３５０ｍｍとして計算した。
【０１０１】
このように、式（８）及び式（１３）に基づいて、光反射部２０ｄ〜２０ｆの面の傾斜角θ₀、θ₁を設定すると、図１３に示すような光強度分布が得られる。図１３は、本実施形態による照明装置の光強度分布の例を示すグラフである。横軸は、線状導光体１４の中心に対する位置を示しており、縦軸は、液晶表示装置から３５０ｍｍ離間した位置で液晶表示装置を視認したときの光強度を示している。
【０１０２】
本実施形態では、区分された領域２２ａ、２２ｂ、２２ｃ内では光反射部２０ｄ、２０ｅ、２０ｆの面の傾斜角θ₀、θ₁が一律に等しい角度に設定されているため、光反射部２０ｄ、２０ｅ、２０ｆの位置が、基準となる位置Ｌ／２、Ｘ_C、Ｌ／６から離間するに伴って、線状導光体１４から光が出射される際の出射角が徐々に大きくなる。このため、本実施形態では、図１４に示すような光強度分布となる。
【０１０３】
図１４から分かるように、本実施形態では、第１乃至第３実施形態による照明装置ほどの光強度分布の均一化は図れないが、図２９に示す提案されている照明装置の光強度分布と比べれば、光強度分布は大幅に均一化されている。
【０１０４】
このように本実施形態による照明装置は、線状導光体１４が長手方向に複数の領域２２ａ、２２ｂ、２２ｃに区分されており、区分された領域２２ａ、２２ｂ、２２ｃ内で光反射部２０ｄ〜２０ｆの面の傾斜角が等しく設定されていることに主な特徴の一つがある。
【０１０５】
第１乃至第３実施形態のように、光反射部の面の傾斜角を、光反射部の位置に応じてそれぞれ設定する場合には、線状導光体を成型するための型等の作製コストが高くなることも考えられる。
【０１０６】
これに対し、本実施形態によれば、光反射部２０ｄ、２０ｅ、２０ｆの面の傾斜角の設定がθ₀とθ₁の２種類と極めて少ないため、線状導光体を成型するための型等のコストを低減することが可能となる。このように、本実施形態によれば、光強度分布を均一化し得る照明装置を簡便かつ安価に提供することができる。
【０１０７】
［第５実施形態］
本発明の第５実施形態による照明装置を図１５乃至図１７を用いて説明する。図１５は、本実施形態による照明装置を示す平面図である。図１６は、本実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。図１７は、本実施形態による照明装置の光強度分布を示すグラフである。図１乃至図１４に示す第１乃至第４実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１０８】
本実施形態による照明装置は、第４実施形態と比べて、線状導光体１４が長手方向により細かく区分されており、領域２２ａ、２２ｃ、２２ｄ、２２ｅ内にそれぞれ複数形成された光反射部２０ｄ、２０ｆ、２０ｇ、２０ｈの面の傾斜角が、区分された領域２２ａ、２２ｃ、２２ｄ、２２ｅ内で等しく設定されていることに主な特徴がある。
【０１０９】
なお、光反射部２０ｄ、２０ｆ、２０ｇ、２０ｈは、線状導光体１４の反射側にそれぞれ多数形成されているが、図１５においては、省略されている。
【０１１０】
領域２２ｄにおいては、領域２２ｄの中心の位置Ｘ_C1を基準として、光反射部２０ｇの面の傾斜角θ₁を設定する。ＬＥＤ１２ａから直接光反射部２０ｇに入射された光が、光反射部２０ｇの面で全反射されて、線状導光体１４の出射側から出射されるものとして、光反射部２０ｇの面の傾斜角θ₁を設定すると、以下のような式が成立する。
【０１１１】
【数１４】

【０１１２】
式（１４）を変形すると、光反射部２０ｇの面の傾斜角θ₁は、以下のような式で表される。
【０１１３】
【数１５】

【０１１４】
領域２２ｈにおいては、領域２２ｈの中心の位置Ｘ_C2を基準として、光反射部２０ｈの面の傾斜角θ₂を設定する。線状導光体１４の出射で全反射された光が、光反射部２０ｈの面で更に全反射されて、線状導光体１４の出射側から出射されるものとして、光反射部２０ｈの面の傾斜角θ₂を設定すると、以下のような式が成立する。
【０１１５】
【数１６】

【０１１６】
式（１６）を変形すると、光反射部２０ｈの面の傾斜角θ₂は、以下のような式で表される。
【０１１７】
【数１７】

【０１１８】
次に、本実施形態による照明装置の光反射部の面の傾斜角の設定値の例について図１６を用いて説明する。図１６は、上記の式に基づいて求められた光反射部の傾斜角の例を示すグラフである。横軸は、線状導光体の端面から光反射部までの距離Ｘ（ｎ）を示しており、縦軸は、光反射部の面の傾斜角を示している。
【０１１９】
なお、本実施形態でも、第１実施形態と同様に、画面サイズを２インチ、表示画面の幅を３５ｍｍ、光反射部２０の数を１５０個、光反射部２０のピッチを０．２３ｍｍ、線状導光体１４の厚さｔを３ｍｍ、線状導光体１４の長さＬを３７ｍｍ、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬを０ｍｍ、線状導光体１４の屈折率を１．５１、視認する人間の目と表示画面との距離を３５０ｍｍとして計算した。
【０１２０】
本実施形態では、区分された領域２２ａ、２２ｃ、２２ｄ、２２ｅ内では、光反射部２０ｄ、２０ｆ、２０ｇ、２０ｈの面の傾斜角θ₀、θ₁、θ₂が一律に等しく設定されているため、光反射部２０ｄ、２０ｆ、２０ｇ、２０ｈの位置が、基準となる位置Ｌ／２、Ｘ_C1、Ｘ_C2、Ｌ／６から離間するに伴って、線状導光体１４から光が出射される際の出射角が徐々に大きくなる。このため、本実施形態では、図１７に示すような光強度分布となる。
【０１２１】
図１７から分かるように、本実施形態では、図１４に示す第４実施形態による照明装置の光強度分布と比較して、光強度の強い部分と弱い部分との差が小さくなっている。
【０１２２】
このことから、本実施形態によれば、第４実施形態と比較して、光強度の強い部分と弱い部分との差を小さくし得ることが分かる。
【０１２３】
このように本実施形態によれば、第４実施形態による照明装置と比較して、線状導光体がより細かく長手方向に区分されているため、第４実施形態に比べて、光強度の強い部分と弱い部分との差を小さくすることができる。
【０１２４】
（変形例）
次に、本実施形態の変形例による照明装置を図１８を用いて説明する。図１８は、本変形例による照明装置を示す平面図である。
【０１２５】
本変形例による照明装置は、領域２２ｄと領域２２ｅとの境界の領域において、傾斜角がθ₁の光反射部２０ｇと、傾斜角がθ₂の光反射部２０ｈとが、交互に設けられていることに主な特徴がある。
【０１２６】
本変形例によれば、領域２２ｄと領域２２ｅとの境界の領域において、傾斜角がθ₁の光反射部２０ｇと、傾斜角がθ₂の光反射部２０ｈとが、交互に設けられているため、領域２２ｄと領域２２ｅとの境界で極端に光強度が相違するのを防止することができる。
【０１２７】
［第６実施形態］
本発明の第６実施形態による照明装置を図１９を用いて説明する。図１９は、本実施形態による照明装置を示す平面図である。図１乃至図１８に示す第１乃至第５実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１２８】
本実施形態による照明装置は、線状導光体１４の反射側、即ち光反射部２０が形成されている側に、線状導光体１４と別個に反射手段２４が設けられていることに主な特徴がある。
【０１２９】
図１９に示すように、本実施形態では、線状導光体１４の反射側に線状導光体１４と別個に反射手段２４が設けられている。反射手段２４としては、線状導光体１４の少なくとも反射側を覆うアルミ製のホルダ等を用いることができる。
【０１３０】
第１乃至第５実施形態では、線状導光体１４の反射側に反射コート膜２０を形成することにより、線状導光体１４の反射側から光が外部に漏れるのを防止していたが、本実施形態では、線状導光体１４と別個に設けられた反射手段２４により、線状導光体１４の反射側から漏れる光が線状導光体１４内に戻されるようになっている。
【０１３１】
このように反射コート膜２０の代わりに反射手段２４を設けた場合であっても、線状導光体１４の反射側から漏れる光を線状導光体１４内に戻すことができるので、照明が全体として暗くなってしまうのを防止することができる。
【０１３２】
このように、線状導光体１４の反射側に必ずしもに反射コート膜２０を形成する必要はなく、本実施形態のように線状導光体１４と別個に反射手段２４を設けてもよい。
【０１３３】
［第７実施形態］
本発明の第７実施形態による照明装置を図２０を用いて説明する。図２０は、本実施形態による照明装置を示す斜視図である。図１乃至図１９に示す第１乃至第６実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１３４】
本実施形態による照明装置は、線状導光体１４の長手方向に対して、光反射部２０ｊが斜めに延在していることに主な特徴がある。
【０１３５】
第１乃至第６実施形態による照明装置では、線状導光体１４の長手方向に対して、光反射部２０が垂直方向に延在していたが、本実施形態では、線状導光体１４の長手方向に対して、光反射部２０ｉが斜めに延在している。
【０１３６】
本実施形態によれば、線状導光体１４の長手方向に対して、光反射部２０ｉが斜めに延在しているため、光強度分布をより均一化することができる。
【０１３７】
［第８実施形態］
本発明の第８実施形態による照明装置を図２１を用いて説明する。図２１は、本実施形態による照明装置を示す平面図である。図１乃至図２０に示す第１乃至第７実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１３８】
本実施形態による照明装置は、線状導光体１４ａの反射側、即ち光反射部２０が形成されている面側が、湾曲していることに主な特徴がある。
【０１３９】
第１乃至第７実施形態による照明装置では、ＬＥＤ１２ａ、１２ｂから離れた位置の光反射部２０においては、他の光反射部２０により光の入射が妨げられる場合があり得る。
【０１４０】
これに対し、本実施形態によれば、線状導光体１４ａの反射側が湾曲しているため、ＬＥＤ１２ａ、１２ｂから離れた位置の光反射部２０であっても、他の光反射部２０により妨げられることなく、光が入射される。従って、本実施形態によれば、より均一な光強度分布が得られる照明装置を提供することができる。
【０１４１】
［第９実施形態］
本発明の第９実施形態による照明装置を図２２を用いて説明する。図２２は、本実施形態による照明装置を示す平面図である。図１乃至図２１に示す第１乃至第８実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１４２】
本実施形態による照明装置は、ＬＥＤ１２ａ、１２ｂから離間するに伴って光反射部２０の面の幅が広くなっている、即ち、ＬＥＤ１２ａ、１２ｂから離間するに伴って光反射部２０を構成する溝が深くなっていることに主な特徴がある。
【０１４３】
図２２に示すように、本実施形態による照明装置では、ＬＥＤ１２ａ、１２ｂの近傍では、光反射部２０を構成する溝の深さがｄ₁に設定されており、ＬＥＤ１２ａ、１２ｂから離間するに伴って、光反射部２０を構成する溝の深さが深くなっている。そして、線状導光体１４ａの中心では、光反射部２０を構成する溝の深さがｄ₁より深いｄ₂に設定されている。
【０１４４】
第１乃至第７実施形態による照明装置では、ＬＥＤ１２ａ、１２ｂから離れた位置の光反射部２０においては、他の光反射部２０により光の入射が妨げられる場合があり得る。
【０１４５】
これに対し、本実施形態によれば、ＬＥＤ１２ａ、１２ｂから離間するに伴って光反射部２０の面の幅が徐々に広くなっているため、ＬＥＤ１２ａ、１２ｂから離れた位置の光反射部２０であっても、他の光反射部２０により妨げられることなく、光が入射される。
【０１４６】
［第１０実施形態］
本発明の第１０実施形態による照明装置を図２３を用いて説明する。図２３は、本実施形態による照明装置を示す斜視図である。図１乃至図２２に示す第１乃至第９実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１４７】
本実施形態による照明装置は、線状導光体１４の反射側の領域が、上下方向、即ち、長手方向と垂直な方向に２段に区分されており、上段側の領域２２ｆでは光反射部２０ｋの傾斜角がθ₀に一律に等しく設定され、下段側の領域２２ｇでは光反射部２２ｌの傾斜角がθ₁に一律に等しく設定されていることに主な特徴がある。
【０１４８】
第４実施形態や第５実施形態による照明装置では、線状導光体１４が長手方向に複数の領域に区分されていたが、本実施形態では、線状導光体１４が上下方向、即ち、長手方向と垂直な方向に複数の領域に区分されている。
【０１４９】
このように線状導光体を上下方向に複数の領域に区分し、区分された領域内で光反射部の傾斜角を一律に等しく設定した場合であっても、光強度分布を均一化することができる。
【０１５０】
［第１１実施形態］
本発明の第１１実施形態による照明装置を図２４及び図２５を用いて説明する。図２４は、本実施形態による照明装置を示す斜視図である。図２５は、本実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。図１乃至図２３に示す第１乃至第１０実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１５１】
本実施形態による照明装置は、光反射部２０ｍ、２０ｎを構成するＶ字形の溝の形状が互いに等しくなっており、線状導光体１４の中心より紙面左側の設けられた光反射部２０ｍについては、紙面左側に設けられたＬＥＤ１２ａから導入される光が線状導光体１４の長手方向に対して垂直な方向に出射されるように、光反射部２０ｍの紙面左側の面の傾斜角θ_L（ｎ）が設定されており、線状導光体１４の中心より紙面右側に設けられた光反射部２０ｎについては、紙面右側に設けられたＬＥＤ１２ｂから導入される光が、線状導光体１４の長手方向に対して垂直な方向に出射されるように、光反射部２０ｎの紙面右側の面の傾斜角θ_R（ｎ）が設定されていることに主な特徴がある。
【０１５２】
なお、光反射部２０ｍ、２０ｎは、線状導光体１４の反射側にそれぞれ多数形成されているが、図２４においては、省略されている。
【０１５３】
図２４に示すように、線状導光体１４の中心より紙面左側に設けられた光反射部２０ｍについては、紙面左側に設けられたＬＥＤ１２ａから導入される光が、光反射部２０ｍの紙面左側の面で反射されて、線状導光体１４の長手方向に対して垂直な方向に出射されるように、光反射部２０ｍの紙面左側の面の傾斜角θ_L（ｎ）が設定されている。
【０１５４】
光反射部２０ｍの紙面左側の面の傾斜角θ_L（ｎ）は、例えば上述した式（２）又は式（４）に基づいて設定すればよい。なお、この場合、線状導光体１４の紙面左側の端面が、距離Ｘ（ｎ）の基準となる。
【０１５５】
一方、線状導光体１４の中心より紙面右側に設けられた光反射部２０ｎについては、紙面右側に設けられたＬＥＤ１２ｂから導入される光が、光反射部２０ｎの紙面右側の面で反射されて、線状導光体１４の長手方向に対して垂直な方向に出射されるように、光反射部２０ｎの紙面右側の面の傾斜角θ_R（ｎ）が設定されている。
【０１５６】
光反射部２０ｎの紙面右側の面の傾斜角θ_R（ｎ）は、例えば上述した式（２）又は式（４）に基づいて設定すればよい。なお、この場合、線状導光体１４の紙面右側の端面が、距離Ｘ（ｎ）の基準となる。
【０１５７】
光反射部２０ｍ、２０ｎを構成するＶ字形の溝の面の交角θ_pは、いずれも等しい角度になっている。
【０１５８】
本実施形態では、光反射部を構成するＶ字形の溝の面の交角θ_pがいずれも等しい角度になっているため、光反射部２０ｍの紙面右側の面の傾斜角は、１８０度から傾斜角θ_L（ｎ）と交角θ_pとを減算した角度となる。このため、ＬＥＤ１２ｂから光反射部２０ｍの紙面右側の面に導入される光は、線状導光体１４の長手方向に対して必ずしも垂直な方向に出射されるとは限らない。
【０１５９】
しかし、ＬＥＤ１２ｂから導入される光については、光反射部２０ｎの紙面右側の面により反射されて、線状導光体１４の長手方向に対して垂直な方向に出射されるため、特段の問題はない。
【０１６０】
また、本実施形態では、光反射部を構成するＶ字形の溝の面の交角θ_pをいずれも等しい角度に設定しているため、光反射部２０ｎの紙面左側の面の傾斜角は、１８０度から傾斜角θ_R（ｎ）と交角θ_pとを減算した角度となる。このため、ＬＥＤ１２ａから光反射部２０ｎの紙面左側の面に導入される光は、線状導光体１４の長手方向に対して必ずしも垂直な方向に出射されるとは限らない。
【０１６１】
しかし、ＬＥＤ１２ａから導入される光は、光反射部２０ｍの紙面左側の面により反射されて、線状導光体の１４の長手方向に対して垂直な方向に出射されるため、特段の問題はない。
【０１６２】
次に、本実施形態による照明装置の光反射部の面の傾斜角の設定値の例について図２５を用いて説明する。図２５は、上記の式に基づいて求められた光反射部の傾斜角の例を示すグラフである。横軸は、線状導光体の端面から光反射部までの距離Ｘ（ｎ）を示しており、縦軸は、光反射部の面の傾斜角を示している。
【０１６３】
なお、本実施形態では、画面サイズを２インチ、表示画面の幅を３５ｍｍ、光反射部２０の数を１７０個、光反射部２０のピッチを０．２１ｍｍ、線状導光体１４の厚さｔを３ｍｍ、線状導光体１４の長さＬを３７ｍｍ、ＬＥＤ１２ａ、１２ｂと線状導光体１４との間の距離ΔＬを０ｍｍ、線状導光体１４の屈折率を１．５１、視認する人間の目と表示画面との距離を３５０ｍｍとして計算した。
【０１６４】
本実施形態によれば、光反射部２０ｍ、２０ｎを構成するＶ字形の溝の形状がいずれも等しいため、線状導光体１４を成型するための型等を作製する際に用いる切削工具が一種類で足りる。本実施形態によれば、線状導光体１４を成型するための型等を低コストで作製することができるため、光強度分布を均一化し得る照明装置を安価に提供することができる。
【０１６５】
［第１２実施形態］
本発明の第１２実施形態による液晶表示装置を図２６を用いて説明する。図２６は、本実施形態による液晶表示装置を示す斜視図である。図１乃至図２５に示す第１乃至第１１実施形態による照明装置と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１６６】
本実施形態による液晶表示装置は、第１乃至第１１実施形態のいずれかによる照明装置と反射型液晶パネルとが組み合わされて構成されている。
【０１６７】
図２６に示すように、反射型液晶パネル２６上には、第１乃至第１１実施形態のいずれかによる照明装置１０が設けられている。
【０１６８】
照明装置１０の線状導光体１４から出射される光は、面状導光体１６を介して反射型液晶パネル２６に入射され、反射型液晶パネル２６に設けられたミラー（図示せず）により反射され、人間の目により視認される。本実施形態では、照明装置１０は、フロントライトとして機能する。
【０１６９】
本実施形態によれば、第１乃至第１１実施形態のいずれかによる照明装置を用いて構成されているため、反射型液晶パネルを均一な光強度で照明することができる。従って、本実施形態によれば、表示特性の良好な液晶表示装置を提供することができる。
【０１７０】
［第１３実施形態］
本発明の第１３実施形態による液晶表示装置を図２７を用いて説明する。図２７は、本実施形態による液晶表示装置を示す斜視図である。図１乃至図２６に示す第１乃至第１２実施形態による照明装置等と同一の構成要素には、同一の符号を付して説明を省略または簡潔にする。
【０１７１】
本実施形態による液晶表示装置は、第１乃至第１１実施形態のいずれかの照明装置と透過型液晶パネルとが組み合わされて構成されている。
【０１７２】
図２７に示すように、第１乃至第１１実施形態のいずれかによる照明装置１０上には、透過型液晶パネル２８が設けられている。
【０１７３】
線状導光体１４から出射される光は、面状導光体１６を介して、透過型液晶パネル２８に入射され、透過型液晶パネル２８を透過して、人間の目により視認される。
【０１７４】
このように本実施形態によれば、透過型液晶パネルを用いた場合であっても、表示特性の良好な液晶表示装置を提供することができる。
【０１７５】
［変形実施形態］
本発明は上記実施形態に限らず種々の変形が可能である。
【０１７６】
例えば、第１０実施形態では、線状導光体を上下方向、即ち、長手方向と垂直な方向に２つの領域に区分したが、更に多くの領域に区分してもよい。これにより、光強度分布をより均一化することが可能となる。但し、区分数を増加するに伴って、光反射部の角度の設定数も多くなるため、要求される光強度分布の均一性と、許容しうるコストとを総合的に考慮して、適切な区分数に設定することが望ましい。
【０１７７】
（付記１） 光を発する光源と、前記光源から導入される光を反射側に形成された複数の光反射部により反射し、前記反射側と対向する出射側から光を線状に出射する線状導光体とを有する照明装置であって、前記複数の光反射部の面が、視認する者の目に光が収束されるような角度で、それぞれ傾斜していることを特徴とする照明装置。
【０１７８】
（付記２） 光を発する光源と、前記光源から導入される光を反射側に形成された複数の光反射部により反射し、前記反射側と対向する出射側から光を線状に出射する線状導光体とを有する照明装置であって、前記複数の光反射部の面が、前記線状導光体の長手方向に対してほぼ垂直な方向に光が出射されるような角度で、それぞれ傾斜していることを特徴とする照明装置。
【０１７９】
（付記３） 付記１又は２記載の照明装置において、前記複数の光反射部は、一方の面が前記光反射部の面である、互いに等しい形状のＶ字形の溝であることを特徴とする照明装置。
【０１８０】
（付記４） 付記１又は２記載の照明装置において、前記線状導光体は長手方向に複数の領域に区分されており、区分された前記領域内では、前記複数の光反射部の面が、等しい角度で傾斜していることを特徴とする照明装置。
【０１８１】
（付記５） 付記４記載の照明装置において、前記線状導光体の中心を含む領域内と、前記線状導光体の端部の近傍の領域内とで、前記複数の光反射部の面が、互いに等しい角度で傾斜していることを特徴とする照明装置。
【０１８２】
（付記６） 付記４記載の照明装置において、前記線状導光体の長手方向に区分された第１の領域では、前記光反射部の面が第１の角度で等しく傾斜しており、前記第１の領域と隣接する第２の領域では、前記光反射部の面が前記第１の角度と異なる第２の角度で等しく傾斜しており、前記第１の領域と前記第２の領域との境界の近傍の領域では、その面が前記第１の角度で傾斜している前記光反射部と、その面が前記第２の角度で傾斜している前記光反射部とが混在していることを特徴とする照明装置。
【０１８３】
（付記７） 付記１又は２記載の照明装置において、前記線状導光体は長手方向と垂直な方向に複数の領域に区分されており、区分された前記領域内では、前記複数の光反射部の面が、等しい角度で傾斜していることを特徴とする照明装置。
【０１８４】
（付記８） 付記１又は２記載の照明装置において、前記光反射部は、前記線状導光体の長手方向に対して斜めに延在していることを特徴とする照明装置。
【０１８５】
（付記９） 付記１記載の照明装置において、前記複数の光反射部の面は、前記光源のほぼ中心から発せられる光が視認する者の目に収束されるような角度で、それぞれ傾斜していることを特徴とする照明装置。
【０１８６】
（付記１０） 付記２記載の照明装置において、前記複数の光反射部の面は、前記光源のほぼ中心から発せられる光が前記線状導光体の長手方向に対してほぼ垂直な方向に出射されるような角度で、それぞれ傾斜していることを特徴とする照明装置。
【０１８７】
（付記１１） 付記１乃至１０のいずれかに記載の照明装置において、前記線状導光体と光学的に結合され、前記線状導光体から導入される光を平面状に出射する面状導光体を更に有することを特徴とする照明装置。
【０１８８】
（付記１２） 付記１乃至１１のいずれかに記載の照明装置において、前記線状導光体は、前記反射側が湾曲していることを特徴とする照明装置。
【０１８９】
（付記１３） 付記１乃至１２のいずれかに記載の照明装置において、一の前記光反射部の面の幅と他の前記光反射部の面の幅とが互いに異なっていることを特徴とする照明装置。
【０１９０】
（付記１４） 付記１乃至１３のいずれかに記載の照明装置において、前記線状導光体の前記反射側に、反射コート膜が更に形成されていることを特徴とする照明装置。
【０１９１】
（付記１５） 付記１乃至１３のいずれかに記載の照明装置において、前記線状導光体の前記反射側に、前記線状導光体と別個に反射手段が更に設けられていることを特徴とする照明装置。
【０１９２】
（付記１６） 付記１乃至１５のいずれかに記載の照明装置において、前記線状導光体は、ほぼ四角柱状に形成されていることを特徴とする照明装置。
【０１９３】
（付記１７） 光を発する光源と、前記光源から導入される光を反射側に形成された複数の光反射部により反射し、前記反射側と対向する出射側から光を線状に出射する線状導光体と、前記線状導光体と光学的に結合され、前記線状導光体から導入される光を平面状に出射する面状導光体とを有する照明装置と、前記照明装置により照明される液晶パネルとを有する液晶表示装置であって、前記複数の光反射部の面が、視認する者の目に光が収束されるような角度で、それぞれ傾斜していることを特徴とする液晶表示装置。
【０１９４】
（付記１８） 光を発する光源と、前記光源から導入される光を反射側に形成された複数の光反射部により反射し、前記反射側と対向する出射側から光を線状に出射する線状導光体と、前記線状導光体と光学的に結合され、前記線状導光体から導入される光を平面状に出射する面状導光体とを有する照明装置と、前記照明装置により照明される液晶パネルとを有する液晶表示装置であって、前記複数の光反射部の面が、前記線状導光体の長手方向に対してほぼ垂直な方向に光が出射されるような角度で、それぞれ傾斜していることを特徴とする液晶表示装置。
【０１９５】
【発明の効果】
以上の通り、本発明によれば、線状導光体から出射される光の出射角が所望の角度となるように光反射部の角度が設定されているため、均一な光強度で照明しうる照明装置を提供することができる。そして、このような照明装置を用いて、表示特性の良好な液晶表示装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態による照明装置を示す斜視図及び平面図である。
【図２】本発明の第１実施形態による照明装置を示す平面図である。
【図３】人間の目と表示画面との関係を示す概略図である。
【図４】空気中における屈折率等を考慮した場合の平面図である。
【図５】本発明の第１実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。
【図６】本発明の第１実施形態による照明装置の光強度分布を示すグラフである。
【図７】本発明の第２実施形態による照明装置を示す平面図である。
【図８】人間の目と表示画面との関係を示す概念図である。
【図９】本発明の第２実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。
【図１０】本発明の第３実施形態による照明装置を示す平面図である。
【図１１】本発明の第３実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。
【図１２】本発明の第４実施形態による照明装置を示す平面図である。
【図１３】本発明の第４実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。
【図１４】本発明の第４実施形態による照明装置の光強度分布を示すグラフである。
【図１５】本発明の第５実施形態による照明装置を示す平面図である。
【図１６】本発明の第５実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。
【図１７】本発明の第５実施形態による照明装置の光強度分布を示すグラフである。
【図１８】本発明の第５実施形態の変形例による照明装置を示す平面図である。
【図１９】本発明の第６実施形態による照明装置を示す平面図である。
【図２０】本発明の第７実施形態による照明装置を示す斜視図である。
【図２１】本発明の第８実施形態による照明装置を示す平面図である。
【図２２】本発明の第９実施形態による照明装置を示す平面図である。
【図２３】本発明の第１０実施形態による照明装置を示す斜視図である。
【図２４】本発明の第１１実施形態による照明装置を示す斜視図である。
【図２５】本発明の第１１実施形態による照明装置の光反射部の面の傾斜角の例を示すグラフである。
【図２６】本発明の第１２実施形態による液晶表示装置を示す斜視図である。
【図２７】本発明の第１３実施形態による液晶表示装置を示す斜視図である。
【図２８】透過型液晶パネル及び反射型液晶パネルを示す断面図である。
【図２９】提案されている照明装置を示す斜視図である。
【図３０】提案されている照明装置の線状導光体を示す斜視図及び平面図である。
【図３１】人間の目と表示画面との関係を示す概略図である。
【図３２】提案されている照明装置の線状導光体から出射される光の強度分布を示すグラフである。
【図３３】提案されている照明装置を示す平面図である。
【符号の説明】
１０…照明装置
１２ａ、１２ｂ…ＬＥＤ
１４…線状導光体
１６…面状導光体
１８…反射コート膜
２０、２０ａ〜２０ｎ…光反射部
２２ａ〜２２ｃ…領域
２４…反射手段
１０８…液晶パネル
１１０…照明装置
１１２ａ、１１２ｂ…ＬＥＤ
１１４…線状導光体
１１６…面状導光体
１１８…反射コート膜
１２０…光反射部
２１０…ガラス基板
２１２…ガラス基板
２１４…偏向子
２１６…バスライン
２１８…ガラス基板
２２０…液晶
２２２…ガラス基板
２２４ａ、２２４ｂ、２２４ｃ…カラーフィルタ
２２６…ガラス基板
２２８…偏向子
２３０…ミラー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an illuminating device and a liquid crystal display device, and more particularly to an illuminating device capable of illuminating with uniform light intensity and a liquid crystal display device using the illuminating device.
[0002]
[Prior art]
Since the liquid crystal panel is thin and lightweight, it is widely used as a display screen of a portable information terminal.
[0003]
Liquid crystal panels include transmissive liquid crystal panels and reflective liquid crystal panels.
[0004]
FIG. 8 (A) is sectional drawing which shows a transmissive liquid crystal panel. FIG. 8 As shown in (a), a deflector 214 is sandwiched between the glass substrate 210 and the glass substrate 212. A bus line 216 and the like are formed on the glass substrate 212. A liquid crystal 220 is sealed between the glass substrate 212 and the glass substrate 218. Color filters 224 a, 224 b, and 224 c are sandwiched between the glass substrate 218 and the glass substrate 222. A deflector 228 is sandwiched between the glass substrate 222 and the glass substrate 226.
[0005]
FIG. 8 (B) is sectional drawing which shows a reflection type liquid crystal panel. FIG. 8 As shown in (b), in the reflective liquid crystal panel, a mirror 230 is sandwiched between the glass substrate 210 and the glass substrate 212. The mirror 230 is for reflecting light introduced from the upper surface of the reflective liquid crystal panel.
[0006]
Since the liquid crystal itself does not emit light, illumination is necessary to view information displayed on the liquid crystal panel.
[0007]
In the transmissive liquid crystal panel, the lighting device is provided on the lower surface side of the liquid crystal panel.
[0008]
In a reflective liquid crystal panel, it is not always necessary to provide a lighting device when viewing a display screen in an environment where sunlight or indoor lighting is present. However, in order to enable visual recognition in an environment where no illumination is present, it is necessary to provide an illumination device. In the reflective liquid crystal panel, the illumination device is provided on the upper surface side of the liquid crystal panel.
[0009]
FIG. 9 FIG. 3 is a perspective view showing a proposed lighting device. FIG. 9 As shown in FIG. 4, the proposed lighting device 110 includes LEDs 112a and 112b that emit light, a linear light guide 114 that converts light from the LEDs 112a and 112b into linear light, and a linear light guide. A planar light guide 116 that converts linear light emitted from the light body 114 into planar light and emits the light. On the back side of the linear light guide 114, that is, on the reflection side, a plurality of light reflecting portions 120 are formed in stripes. A reflective coating film 118 is formed on the reflective side of the linear light guide 114.
[0010]
FIG. 30 is a perspective view and a plan view showing a linear light guide of the proposed lighting device. As shown in FIG. 30, the light emitted from the LEDs 112 a and 112 b is reflected on the back surface side of the linear light guide 114, that is, the surface of the light reflecting portion 120 formed on the reflection side, and the linear light guide 114. The light is emitted from the front side, that is, from the emission side. Light emitted linearly from the emission side of the linear light guide 114 is converted into planar light by the planar light guide 116 and emitted from the plane of the planar light guide 116.
[0011]
In such a proposed illumination device, the liquid crystal panel can be illuminated in a planar shape.
[0012]
Such an illuminating device is described in, for example, Japanese Patent Laid-Open No. 10-260405.
[0013]
[Problems to be solved by the invention]
However, the proposed illumination device described above cannot illuminate the liquid crystal panel with uniform intensity as described below.
[0014]
FIG. 31 is a schematic diagram showing the relationship between the human eye and the display screen. When viewing the display screen of the liquid crystal panel 108 having a screen size of 2 inches from a position separated by 350 mm, 0 degree light reaches the eyes from the center of the display screen, and ± 3 degrees light is visible from both ends of the display screen. To reach.
[0015]
FIG. 32 is a graph showing the intensity distribution of light emitted from the linear light guide of the proposed lighting device. The horizontal axis indicates the position from the center of the linear light guide 114, and the vertical axis indicates the light intensity. Here, the light emitted from the center of the linear light guide 114 reaches the eye at 0 degree, and the light emitted from the end of the linear light guide 114 has a light of ± 3 degrees. In order to reach the eye, a light intensity distribution that can actually reach the human eye is required.
[0016]
As shown in FIG. 32, in the proposed illuminating device, the intensity distribution of the light emitted from the linear light guide 114 is not uniform, and there are a strong portion and a weak portion. The intensity distribution of light emitted from the linear light guide 114 is reflected in the intensity distribution of light emitted from the planar light guide 116. For this reason, the intensity distribution of the light emitted from the planar light guide 116 is not uniform, and there are a strong portion and a weak portion in the plane. Therefore, when a liquid crystal display device is configured using the proposed illumination device, good display characteristics cannot be obtained.
[0017]
An object of the present invention is to provide an illumination device that can illuminate with uniform light intensity and a liquid crystal display device having good display characteristics using the illumination device.
[0018]
[Means for Solving the Problems]
The object is to reflect a light source that emits light and a plurality of light reflecting portions formed on the reflection side of the light introduced from the light source, and to emit light in a linear form from the emission side facing the reflection side. A planar light guide and a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape, The light emitted from the light source is introduced into the linear light guide through the end of the linear light guide, and the light emitted from the planar light guide converges to the eyes of the viewer. The surfaces of the plurality of light reflecting portions are inclined at a plurality of different angles according to the positions of the light reflecting portions, respectively. Each of the plurality of light reflecting portions is formed of a V-shaped groove having an equal intersection angle, and one surface of the V-shaped groove is a surface of the light reflecting portion. This is achieved by a lighting device characterized in that.
[0019]
Further, the above object is to reflect light from a light source that emits light and a plurality of light reflecting portions formed on the reflection side of the light introduced from the light source, and to emit light in a linear form from the emission side facing the reflection side. And a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape. Then, light emitted from the light source is introduced into the linear light guide through the end of the linear light guide, and in a direction substantially perpendicular to the longitudinal direction of the linear light guide. The surfaces of the plurality of light reflecting portions are inclined at a plurality of different angles according to the positions of the light reflecting portions so that light is emitted. Each of the plurality of light reflecting portions is formed of a V-shaped groove having an equal intersection angle, and one surface of the V-shaped groove is a surface of the light reflecting portion. This is achieved by a lighting device characterized in that.
[0020]
Further, the above object is to reflect light from a light source that emits light and a plurality of light reflecting portions formed on the reflection side of the light introduced from the light source, and to emit light in a linear form from the emission side facing the reflection side. A linear light guide, and a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape; A liquid crystal display device having a liquid crystal panel illuminated by the illumination device, wherein light emitted from the light source is introduced into the linear light guide through an end of the linear light guide, The surfaces of the plurality of light reflecting portions are respectively at a plurality of different angles according to the positions of the light reflecting portions so that the light emitted from the planar light guide is converged to the eyes of a viewer. Tilt Each of the plurality of light reflecting portions is formed of a V-shaped groove having an equal intersection angle, and one surface of the V-shaped groove is a surface of the light reflecting portion. This is achieved by a liquid crystal display device.
[0021]
Further, the above object is to reflect light from a light source that emits light and a plurality of light reflecting portions formed on the reflection side of the light introduced from the light source, and to emit light in a linear form from the emission side facing the reflection side. A linear light guide, and a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape; A liquid crystal display device having a liquid crystal panel illuminated by the illumination device, wherein light emitted from the light source is introduced into the linear light guide through an end of the linear light guide, The surfaces of the plurality of light reflecting portions are at a plurality of different angles according to the positions of the light reflecting portions so that light is emitted in a direction substantially perpendicular to the longitudinal direction of the linear light guide. Each inclined Each of the plurality of light reflecting portions is formed of a V-shaped groove having an equal intersection angle, and one surface of the V-shaped groove is a surface of the light reflecting portion. This is achieved by a liquid crystal display device.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
[Principle of the present invention]
Prior to describing the lighting apparatus according to the first embodiment of the present invention, the principle of the present invention will be described.
[0023]
The present inventors diligently studied why the proposed lighting device cannot illuminate the liquid crystal panel with uniform light intensity.
[0024]
FIG. 33 is a plan view showing a proposed lighting device.
[0025]
With respect to the surface of the light reflecting portion 120 formed at the position A, which is the center of the linear light guide body 114, the trajectory of the light beam is traced by reverse ray tracing with the exit angle set to 0 degree. Reached the center.
[0026]
Further, when the light trajectory is traced by reverse ray tracing with respect to the surface of the light reflecting portion 120 formed at the position C which is near the left end of the linear light guide 114, the trajectory is the LED 112a. Almost reached the center of the. Note that the reverse ray tracing was performed at an exit angle of 3 degrees when the 2-inch liquid crystal panel was viewed from a position 350 mm away from the display screen, and the light reaching the human eye had an exit angle of approximately 3 It is because it is light of degree.
[0027]
Further, the light reflecting portion formed at the position B which is an intermediate position between the position A and the position C 120 When the light trajectory was traced by reverse ray tracing with an emission angle of 1.5 degrees, for example, the trajectory reached a position shifted from the center of the LED 112a.
[0028]
On the other hand, when the intensity of light emitted from the position A at an emission angle of about 0 degrees was examined, the intensity of the emitted light was high. Further, when the intensity of the light having an emission angle of about 3 degrees emitted from the position C was examined, the intensity of the emitted light was high. Further, when the intensity of the light having an emission angle of about 1.5 degrees emitted from the position B was examined, the intensity of the emitted light was weak.
[0029]
From the above, when the trajectory of light obtained by back ray tracing with the angle at which light can reach the human eye as the exit angle reaches the vicinity of the center of the LED, the intensity of light that can reach the human eye It is clear that the intensity of light that can reach the human eye is weak when the light trajectory required by back ray tracing deviates from the center of the LED with the angle at which light can reach the human eye as the exit angle. It was.
[0030]
Based on such examination results, the inventors of the present application have determined that the light reflecting portion of the light reflecting portion reaches the vicinity of the center of the LED so that the trajectory of light obtained by back ray tracing with the angle at which light can reach the human eye as the exit angle. It was conceived that if the inclination angle of the surface is set, the light is converged on the eyes of the human being visually recognized and a uniform light intensity distribution can be obtained.
[0031]
[First Embodiment]
A lighting device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view and a plan view showing the lighting apparatus according to the present embodiment. FIG. 1A is a perspective view showing the lighting apparatus according to the present embodiment. FIG.1 (b) is a top view which shows the illuminating device by this embodiment. FIG. 2 is a plan view showing the lighting apparatus according to the present embodiment. FIG. 2A is a plan view showing the configuration of the illumination device according to the present embodiment. FIG. 2B is a diagram illustrating the inclination angle of the light reflecting portion of the illumination device according to the present embodiment. FIG. 3 is a schematic diagram showing the relationship between the human eye and the display screen. FIG. 4 is a plan view when the refractive index in the air is taken into consideration. FIG. 5 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment. FIG. 6 is a graph showing the light intensity distribution of the lighting apparatus according to the present embodiment.
[0032]
As shown in FIG. 1, the illumination device 10 according to the present embodiment includes LEDs 12 a and 12 b that emit light, and a linear light guide body 14 that converts light emitted from the LEDs 12 a and 12 b into linear light and emits the light. And a planar light guide 16 that is optically coupled to the linear light guide 14 and converts linear light into planar light and emits the light. A reflective coating film 18 is formed on the reflective side of the linear light guide 14.
[0033]
The LEDs 12 a and 12 b are provided at both ends of the linear light guide 14. A distance ΔL (see FIG. 2) between the LEDs 12a and 12b and the linear light guide 14 is set to 0 mm, for example.
[0034]
The linear light guide 14 is formed in a quadrangular prism shape as a whole. As a material of the linear light guide 14, for example, glass or plastic is used. Refractive index N of the linear light guide 14 _g Is, for example, 1.51. The thickness t of the linear light guide 14 is set to 3 mm, for example. The length L of the linear light guide 14 is set to 37 mm, for example, in the case of a lighting device used for a 2-inch liquid crystal display device, for example. The width of the display screen of the 2-inch liquid crystal display device is about 35 mm, but if the length L of the linear light guide 14 is set to 37 mm, a margin of 2 mm is secured.
[0035]
On the reflection side of the linear light guide 14, a plurality of light reflecting portions 20 are formed in a stripe shape. The light reflecting section 20 is for reflecting light introduced from the LEDs 12 a and 12 b and emitting light from the emission side of the linear light guide 14. For example, 150 light reflecting portions 20 are formed at a pitch of 0.23 mm, for example.
[0036]
As shown in FIG. 2, the inclination angle θ (n) of the surfaces of the light reflecting portions 20a and 20b is set to a desired emission angle θ according to the emission position. _OUT It is set so that light is emitted in (n). In addition, although many light reflection parts 20a and 20b are each formed in the reflective side of the linear light guide 14, it is abbreviate | omitted in FIG.
[0037]
As shown in FIG. 3, when viewing a 2-inch liquid crystal panel from a position 350 mm away, human eyes receive 0 ° light from the center of the display screen and ± 2. Eight degrees of light is incident.
[0038]
Output angle θ of light emitted from the linear light guide 14 _OUT (N) is reflected in the emission angle of the light emitted from the planar light guide 16. For this reason, for the light emitted from the center of the linear light guide 14, the emission angle θ _OUT For the light emitted from the position between the center and the end of the linear light guide 14 by setting the inclination angle θ (n) of the surface of the light reflecting portion 20 so that (n) is, for example, 0 degree. Is the exit angle θ _OUT The angle of inclination θ (n) of the surface of the light reflecting portion 20 is set so that (n) becomes an angle corresponding to each emission position, and light emitted from the vicinity of the end of the linear light guide 14 For the exit angle θ _OUT If the inclination angle θ (n) of the surface of the light reflecting portion 20 is set so that (n) is, for example, ± 2.8 degrees, extremely good display characteristics can be obtained.
[0039]
Output angle θ of light emitted from the linear light guide 14 _OUT In order to set (n) to an angle corresponding to the emission position, the inclination angle θ (n) may be obtained based on the following equation.
[0040]
As shown in FIG. 2, with respect to the light reflecting portion 20 a, the light totally reflected on the surface on the emission side of the linear light guide 14 is totally reflected by the light reflecting portion 20 a, and Output angle θ according to output position from output side _OUT The inclination angle θ (n) of the surface of the light reflecting portion 20a is set so as to be emitted at (n).
[0041]
In this case, the following formula is established.
[0042]
[Expression 1]

[0043]
Here, n means that it relates to the nth light reflecting portion. X (n) is the distance from the end face of the linear light guide 14 to the nth light reflecting portion. And θ _OUT (N) is an emission angle of the light reflected by the nth light reflecting portion.
[0044]
When formula (1) is transformed, the inclination angle θ (n) of the surface of the light reflecting portion 20a is expressed by the following formula.
[0045]
[Expression 2]

[0046]
As for the light reflecting portion 20b, the light that is directly incident on the light reflecting portion 20b from the LED 12a is totally reflected on the surface of the light reflecting portion 20b, and the emission angle corresponding to the emission position from the emission side of the linear light guide 14 θ _OUT The inclination angle θ (n) of the surface of the light reflecting portion 20b is set so as to be emitted at (n).
[0047]
In this case, the following formula is established.
[0048]
[Equation 3]

[0049]
When Expression (3) is transformed, the inclination angle θ (n) of the surface of the light reflecting portion 20b is expressed by the following expression.
[0050]
[Expression 4]

[0051]
As shown in FIG. 2B, the inclination angle θ of the surface on the left side of the paper of the light reflecting portion. _L For (n), the light introduced from the LED 12a provided on the left side of the page is the desired emission angle θ. _OUT It sets so that it may radiate | emit by (n). On the other hand, the tilt angle θ of the right side surface of the light reflecting portion _R With regard to (n), the light introduced from the LED 12b provided on the right side of the paper is the desired emission angle θ. _OUT It sets so that it may radiate | emit by (n).
[0052]
Strictly, as shown in FIG. 4, when the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is not 0 mm, the refractive index N in the air _a And the refractive index N of the linear light guide _g Since the refractive index differs between and, the optical path shifts. However, the deviation of the optical path due to such factors can be ignored in obtaining the inclination angle θ (n) of the surface of the light reflecting portion 20. For this reason, here, in order to simplify the calculation formula, the calculation formula is established ignoring the influence of such factors.
[0053]
Strictly speaking, as shown in FIG. 4, light is emitted in a planar shape from the vicinity of the centers of the LEDs 12a and 12b. However, in obtaining the inclination angle θ (n) of the surface of the light reflecting section 20, even if a calculation formula is established assuming that light is emitted from the center point of the LEDs 12a and 12b, the error is negligibly small. For this reason, in order to simplify the calculation formula, the calculation formula is set up assuming that light is emitted from the center point of the LEDs 12a and 12b.
[0054]
Next, an example of a specific set value of the inclination angle θ (n) of the surface of the light reflecting section 20 of the present embodiment will be described with reference to FIG. FIG. 5 is a graph showing an example of the inclination angle θ (n) of the surface of the light reflecting portion obtained based on the above formula. The horizontal axis indicates the distance X (n) from the end face of the linear light guide 14 to the light reflecting portion 20, and the vertical axis indicates the inclination angle θ (n) of the surface of the light reflecting portion 20. .
[0055]
Here, the screen size is 2 inches, the width of the display screen is 35 mm, the number of the light reflecting portions 20 is 150, the pitch of the light reflecting portions 20 is 0.23 mm, the thickness t of the linear light guide 14 is 3 mm, The length L of the linear light guide 14 is 37 mm, the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is 0 mm, the refractive index of the linear light guide 14 is 1.51, and the human eye that is visually recognized The distance between the eyes and the display screen was calculated as 350 mm.
[0056]
If the inclination angle θ (n) of the surface of the light reflecting portion 20 is set as shown in FIG. 5, a light intensity distribution as shown in FIG. 6 is obtained. FIG. 6 is a graph showing the light intensity distribution of the lighting apparatus according to the present embodiment. The horizontal axis indicates the position in the linear light guide, and the vertical axis indicates the light intensity. Here, the light emitted from the center of the linear light guide 14 reaches the eyes, and the light emitted from the end of the linear light guide 14 is ± 2.8 degrees. As the light reaches the eye, a light intensity distribution that can actually reach the human eye is required.
[0057]
As can be seen from FIG. 6, in the illumination device according to the present embodiment, a substantially uniform light intensity distribution is obtained.
[0058]
Thus, the illumination device according to the present embodiment has a desired emission angle θ according to the emission position of the light emitted from the linear light guide 14. _OUT The light reflecting portion so that light is emitted in (n). 20 The main feature is that the inclination angle θ (n) of the surface is set.
[0059]
In the proposed illuminating device shown in FIG. 29, since the surfaces of the light reflecting portions are all set to the same inclination angle α (see FIG. 31), light is emitted at a desired emission angle according to the emission position. I couldn't. For this reason, in the proposed illumination device, the intensity distribution of light that can reach the eyes of a human being visually recognized cannot be made uniform.
[0060]
On the other hand, in the present embodiment, a desired emission angle θ according to the emission position of the light emitted from the linear light guide 14. _OUT The light reflecting portion so that light is emitted in (n). 20 Since the inclination angle θ (n) of the surface is set, the light can be converged on the eyes of the human being visually recognized. For this reason, according to the present embodiment, the light intensity distribution that can reach the human eye can be made uniform. Therefore, according to the present embodiment, good display characteristics can be realized.
[0061]
[Second Embodiment]
A lighting device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a plan view showing the lighting apparatus according to the present embodiment. FIG. 8 is a conceptual diagram showing the relationship between the human eye and the display screen. FIG. 9 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment. The same components as those of the lighting apparatus according to the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0062]
The illuminating device according to the present embodiment has an emission angle θ of light emitted from the linear light guide 14. _OUT The angle of inclination θ (n) of the surface of the light reflecting portion 20 is set so that (n) is 0 degrees, that is, light is emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14. The main feature is that
[0063]
In the illuminating device according to the first embodiment, the output angle θ depends on the output position. _OUT Although the inclination angle θ (n) of the surface of the light reflecting portion 20 is set so that (n) becomes a desired angle, the position of the human eye viewing the display screen is not necessarily a planar light guide. It does not necessarily coincide with the normal direction of the body 16. On the other hand, the output angle θ _OUT Even if (n) is uniformly set to 0 degrees, the light spreads to some extent until it reaches the human eye that is 350 mm away from the display screen, so in fact, the same light intensity distribution as in the first embodiment is obtained. It is done. Also, the exit angle θ _OUT If (n) is set uniformly, the calculation for obtaining the inclination angle θ (n) of the surface of the light reflecting portion 20 can be facilitated.
[0064]
Therefore, in this embodiment, the emission angle θ _OUT (N) is uniformly set to 0 degrees.
[0065]
In this embodiment, the output angle θ _OUT In order to set (n) to 0 degrees, θ in Equations (2) and (4) _OUT (N) = 0 degree may be substituted.
[0066]
Θ in equation (2) _OUT When (n) = 0 degrees is substituted, the inclination angle θ (n) of the surface of the light reflecting portion 20a is expressed by the following equation.
[0067]
[Equation 5]

[0068]
Also, in equation (4), θ _OUT When (n) = 0 degrees is substituted, the inclination angle θ (n) of the surface of the light reflecting portion 20b is expressed by the following equation.
[0069]
[Formula 6]

[0070]
Next, an example of the set value of the tilt angle θ (n) of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment will be described with reference to FIG. FIG. 9 is a graph showing an example of the inclination angle θ (n) of the surface of the light reflecting portion obtained based on the above formula. The horizontal axis indicates the distance from the end face of the linear light guide 14 to the light reflecting portions 20a and 20b, and the vertical axis indicates the inclination angle θ (n) of the surfaces of the light reflecting portions 20a and 20b. .
[0071]
In the present embodiment, similarly to the first embodiment, the screen size is 2 inches, the width of the display screen is 35 mm, the number of the light reflecting portions 20 is 150, the pitch of the light reflecting portions 20 is 0.23 mm, and the line The thickness t of the linear light guide 14 is 3 mm, the length L of the linear light guide 14 is 37 mm, the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is 0 mm, and the linear light guide 14 The refractive index is 1.51, and the distance between the human eye to be viewed and the display screen is 350 mm.
[0072]
When the inclination angle θ (n) of the surfaces of the light reflecting portions 20a and 20b is set as shown in FIG. 9, the emission angle θ of the light emitted from the linear light guide 14 _OUT Both (n) are 0 degrees, and a uniform light intensity distribution is obtained in substantially the same manner as in the first embodiment. Therefore, according to the present embodiment, good display characteristics can be realized as in the first embodiment.
[0073]
[Third Embodiment]
A lighting device according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a plan view showing the lighting apparatus according to the present embodiment. FIG. 11 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment. The same components as those of the illumination device according to the first or second embodiment shown in FIGS. 1 to 9 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0074]
The illuminating device according to the present embodiment directly directs the light reflecting portion 20 from the LEDs 12a and 12b for any light reflecting portion 20c. c The angle of inclination θ (n) of the surface of the light reflecting portion 20c is set so that the light incident on the light is totally reflected by the light reflecting portion 20c and emitted from the emitting side of the linear light guide body 14. The main feature is that
[0075]
In the illuminating device according to the first and second embodiments, the light reflecting portion 20a in which the inclination angle θ (n) is set so as to further totally reflect the light totally reflected on the light-emitting side surface of the linear light guide 14. And the light reflection part 20b in which the inclination angle θ (n) is set so as to totally reflect light directly incident from the LEDs 12a and 12b.
[0076]
On the other hand, in the present embodiment, as shown in FIG. 10, the inclination angle of the surface of the light reflecting portion 20c is totally reflected for any light reflecting portion 20c so that the light directly incident from the LEDs 12a and 12b is totally reflected. θ (n) is set. In addition, although many light reflection parts 20c are formed in the reflective side of the linear light guide 14, it is abbreviate | omitted in FIG.
[0077]
In this case, the inclination angle θ (n) of the surface of the light reflecting portion 20c may be set based on the above-described equation (4) or equation (6).
[0078]
Next, an example of a set value of the inclination angle θ (n) of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment will be described with reference to FIG. FIG. 11 is a graph showing an example of the inclination angle θ (n) of the surface of the light reflecting portion obtained based on the above formula. The horizontal axis indicates the distance X (n) from the end surface of the linear light guide 14 to the light reflecting portion 20c, and the vertical axis indicates the inclination angle θ (n) of the surface of the light reflecting portion 20c. .
[0079]
In the present embodiment, similarly to the first embodiment, the screen size is 2 inches, the width of the display screen is 35 mm, the number of the light reflecting portions 20 is 150, the pitch of the light reflecting portions 20 is 0.23 mm, and the line The thickness t of the linear light guide 14 is 3 mm, the length L of the linear light guide 14 is 37 mm, the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is 0 mm, and the linear light guide 14 The refractive index is 1.51, and the distance between the human eye to be viewed and the display screen is 350 mm.
[0080]
Thus, even when the inclination angle θ (n) of the surface of the light reflecting portion 20c is set, the emission angle θ of the light emitted from the linear light guide 14 _OUT Are 0 degrees, and a uniform light intensity distribution is obtained in substantially the same manner as in the first and second embodiments. Therefore, according to the present embodiment, good display characteristics can be realized as in the first and second embodiments.
[0081]
[Fourth Embodiment]
A lighting device according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a plan view showing the lighting apparatus according to the present embodiment. FIG. 13 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment. FIG. 14 is a graph showing the light intensity distribution of the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to third embodiments shown in FIGS. 1 to 11 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0082]
In the illumination device according to the present embodiment, the linear light guide 14 is divided into a plurality of regions 22a, 22b, and 22c in the longitudinal direction, and a plurality of light reflecting portions 20d to 20c are formed in the regions 22a, 22b, and 22c, respectively. The main feature is that the inclination angle of the surface 20f is set to be equal in the divided regions 22a, 22b, and 22c.
[0083]
In addition, although many light reflection parts 20d-20f are each formed in the reflective side of the linear light guide 14, it is abbreviate | omitted in FIG.
[0084]
In the region 22c including the center of the linear light guide 14, the inclination angle θ of the surface of the light reflecting portion 20f with reference to the center position L / 2 of the linear light guide 14. ₀ Set. Assuming that the light totally reflected by the light-emitting surface of the linear light guide 14 is totally reflected by the light reflecting portion 20f and emitted from the light-emitting side of the linear light guide 14, the light reflecting portion 20f Inclination angle of surface θ ₀ When is set, the following equation is established.
[0085]
[Expression 7]

[0086]
When the equation (7) is transformed, the inclination angle θ of the surface of the light reflecting portion 20f ₀ Is represented by the following equation.
[0087]
[Equation 8]

[0088]
In addition, in the region 22a in the vicinity of the end portion of the linear light guide 14, the inclination angle of the surface of the light reflecting portion 20d is based on the position where the distance from the end of the linear light guide 14 is L / 6. θ ′ ₀ Set. Assuming that light that is directly incident on the light reflecting portion 20d from the LED 12a is totally reflected by the light reflecting portion 20d and emitted from the emitting side of the linear light guide 14, the inclination angle θ of the surface of the light reflecting portion 20d ′ ₀ When is set, the following equation is established.
[0089]
[Equation 9]

[0090]
When the equation (9) is transformed, the inclination angle θ ′ of the surface of the light reflecting portion 20d ₀ Is represented by the following equation.
[0091]
[Expression 10]

[0092]
Here, when the equation (8) is compared with the equation (10), since the value of ΔL is extremely small, ΔL and 3 · ΔL can be ignored, and the following equation is established.
[0093]
## EQU11 ##

[0094]
Therefore, also in the region 22a in the vicinity of the end portion of the linear light guide 14, the inclination angle of the surface of the light reflecting portion 20d is set to θ based on the equation (8). ₀ It will be sufficient to set to. Therefore, in the present embodiment, the inclination angle of the surface of the light reflecting portion 20f in the region 22c including the center of the linear light guide 14 and the light reflecting portion 20d in the region 22a in the vicinity of the end of the linear light guide 14. The angle of inclination of the surface of ₀ Should be set.
[0095]
Further, in the region 22b between the region 22a and the region 22c, the position of the center of the region 22b (X _C ) As a reference, the inclination angle θ of the surface of the light reflecting portion 20e ₁ Set. Assuming that light that is directly incident on the light reflecting portion 20e from the LED 12a is totally reflected by the light reflecting portion 20e and emitted from the emitting side of the linear light guide 14, the inclination angle θ of the surface of the light reflecting portion 20e ₁ When is set, the following equation is established.
[0096]
[Expression 12]

[0097]
When the equation (12) is transformed, the inclination angle θ of the surface of the light reflecting portion 20e ₁ Is represented by the following equation.
[0098]
[Formula 13]

[0099]
Next, an example of the setting value of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment will be described with reference to FIG. FIG. 13 is a graph showing an example of the inclination angle θ of the surface of the light reflecting portion obtained based on the above formula. The horizontal axis indicates the distance X (n) from the end face of the linear light guide to the light reflecting portion, and the vertical axis indicates the inclination angle θ of the surface of the light reflecting portion.
[0100]
In the present embodiment, similarly to the first embodiment, the screen size is 2 inches, the width of the display screen is 35 mm, the number of the light reflecting portions 20 is 150, the pitch of the light reflecting portions 20 is 0.23 mm, and the line The thickness t of the linear light guide 14 is 3 mm, the length L of the linear light guide 14 is 37 mm, the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is 0 mm, and the linear light guide 14 The refractive index is 1.51, and the distance between the human eye to be viewed and the display screen is 350 mm.
[0101]
Thus, based on Expression (8) and Expression (13), the inclination angle θ of the surfaces of the light reflecting portions 20d to 20f ₀ , Θ ₁ Is set, a light intensity distribution as shown in FIG. 13 is obtained. FIG. 13 is a graph showing an example of the light intensity distribution of the lighting apparatus according to the present embodiment. The horizontal axis indicates the position with respect to the center of the linear light guide 14, and the vertical axis indicates the light intensity when the liquid crystal display device is viewed at a position spaced 350 mm from the liquid crystal display device.
[0102]
In the present embodiment, the inclined angles θ of the surfaces of the light reflecting portions 20d, 20e, and 20f in the divided regions 22a, 22b, and 22c. ₀ , Θ ₁ Are uniformly set at the same angle, the positions of the light reflecting portions 20d, 20e, 20f are the reference positions L / 2, X _C As the distance from L / 6 increases, the emission angle when light is emitted from the linear light guide 14 gradually increases. For this reason, in this embodiment, it becomes light intensity distribution as shown in FIG.
[0103]
As can be seen from FIG. 14, in this embodiment, the light intensity distribution as uniform as the lighting apparatus according to the first to third embodiments cannot be made uniform, but the light intensity distribution of the proposed lighting apparatus shown in FIG. In comparison, the light intensity distribution is greatly uniformed.
[0104]
As described above, in the illumination device according to the present embodiment, the linear light guide 14 is divided into the plurality of regions 22a, 22b, and 22c in the longitudinal direction, and the light reflecting portion 20d is divided in the divided regions 22a, 22b, and 22c. One of the main features is that the inclination angles of the surfaces of ˜20f are set equal.
[0105]
As in the first to third embodiments, when the inclination angle of the surface of the light reflecting portion is set according to the position of the light reflecting portion, a mold or the like for molding the linear light guide is produced. The cost may be high.
[0106]
On the other hand, according to the present embodiment, the setting of the inclination angle of the surfaces of the light reflecting portions 20d, 20e, and 20f is θ. ₀ And θ ₁ Therefore, it is possible to reduce the cost of a mold for molding the linear light guide. Thus, according to the present embodiment, it is possible to provide a lighting device that can make the light intensity distribution uniform easily and inexpensively.
[0107]
[Fifth Embodiment]
An illumination device according to a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a plan view showing the lighting apparatus according to the present embodiment. FIG. 16 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment. FIG. 17 is a graph showing the light intensity distribution of the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to fourth embodiments shown in FIGS. 1 to 14 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0108]
In the illumination device according to the present embodiment, the linear light guides 14 are more finely divided in the longitudinal direction than in the fourth embodiment, and a plurality of light reflecting portions formed in the regions 22a, 22c, 22d, and 22e, respectively. The main feature is that the inclination angles of the surfaces 20d, 20f, 20g, and 20h are set to be equal in the divided regions 22a, 22c, 22d, and 22e.
[0109]
In addition, although many light reflection parts 20d, 20f, 20g, and 20h are each formed in the reflective side of the linear light guide 14, they are abbreviate | omitted in FIG.
[0110]
In the region 22d, the position X of the center of the region 22d _C1 Is the inclination angle θ of the surface of the light reflecting portion 20g ₁ Set. It is assumed that the light that is directly incident on the light reflecting portion 20g from the LED 12a is totally reflected on the surface of the light reflecting portion 20g and is emitted from the emitting side of the linear light guide 14, and the surface of the light reflecting portion 20g is inclined. Angle θ ₁ When is set, the following equation is established.
[0111]
[Expression 14]

[0112]
When the equation (14) is transformed, the inclination angle θ of the surface of the light reflecting portion 20g ₁ Is represented by the following equation.
[0113]
[Expression 15]

[0114]
In the region 22h, the position X of the center of the region 22h _C2 As a reference, the inclination angle θ of the surface of the light reflecting portion 20h ₂ Set. The light totally reflected by the emission of the linear light guide 14 is further totally reflected by the surface of the light reflection portion 20h and emitted from the emission side of the linear light guide 14. The light reflection portion 20h Inclination angle of surface θ ₂ When is set, the following equation is established.
[0115]
[Expression 16]

[0116]
When the equation (16) is transformed, the inclination angle θ of the surface of the light reflecting portion 20h ₂ Is represented by the following equation.
[0117]
[Expression 17]

[0118]
Next, an example of the set value of the tilt angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment will be described with reference to FIG. FIG. 16 is a graph showing an example of the inclination angle of the light reflecting portion obtained based on the above formula. The horizontal axis indicates the distance X (n) from the end surface of the linear light guide to the light reflecting portion, and the vertical axis indicates the inclination angle of the surface of the light reflecting portion.
[0119]
In the present embodiment, similarly to the first embodiment, the screen size is 2 inches, the width of the display screen is 35 mm, the number of the light reflecting portions 20 is 150, the pitch of the light reflecting portions 20 is 0.23 mm, and the line The thickness t of the linear light guide 14 is 3 mm, the length L of the linear light guide 14 is 37 mm, the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is 0 mm, and the linear light guide 14 The refractive index is 1.51, and the distance between the human eye to be viewed and the display screen is 350 mm.
[0120]
In the present embodiment, in the divided regions 22a, 22c, 22d, and 22e, the inclination angles θ of the surfaces of the light reflecting portions 20d, 20f, 20g, and 20h ₀ , Θ ₁ , Θ ₂ Are uniformly set, the positions of the light reflecting portions 20d, 20f, 20g, and 20h are the reference positions L / 2, X _C1 , X _C2 As the distance from L / 6 increases, the emission angle when light is emitted from the linear light guide 14 gradually increases. For this reason, in this embodiment, it becomes light intensity distribution as shown in FIG.
[0121]
As can be seen from FIG. 17, in this embodiment, the difference between the strong and weak portions of the light intensity is smaller than the light intensity distribution of the illumination device according to the fourth embodiment shown in FIG.
[0122]
From this, it can be seen that, according to the present embodiment, the difference between the light intensity portion and the weak portion can be reduced as compared with the fourth embodiment.
[0123]
As described above, according to the present embodiment, the linear light guide is more finely divided in the longitudinal direction than the illumination device according to the fourth embodiment, so that the light intensity is higher than that of the fourth embodiment. The difference between the strong part and the weak part can be reduced.
[0124]
(Modification)
Next, an illumination device according to a modification of the present embodiment will be described with reference to FIG. FIG. 18 is a plan view showing an illumination device according to this modification.
[0125]
In the illumination device according to this modification, the inclination angle is θ in the boundary region between the region 22d and the region 22e. ₁ The light reflecting portion 20g and the inclination angle is θ ₂ The main feature is that the light reflecting portions 20h are alternately provided.
[0126]
According to the present modification, the inclination angle is θ in the boundary region between the region 22d and the region 22e. ₁ The light reflecting portion 20g and the inclination angle is θ ₂ Since the light reflecting portions 20h are alternately provided, it is possible to prevent the light intensity from being extremely different at the boundary between the region 22d and the region 22e.
[0127]
[Sixth Embodiment]
An illumination device according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 19 is a plan view showing the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to fifth embodiments shown in FIGS. 1 to 18 are denoted by the same reference numerals, and description thereof will be omitted or simplified.
[0128]
The illuminating device according to the present embodiment is provided with the reflecting means 24 separately from the linear light guide 14 on the reflection side of the linear light guide 14, that is, on the side where the light reflecting portion 20 is formed. There are main features.
[0129]
As shown in FIG. 19, in the present embodiment, the reflecting means 24 is provided separately from the linear light guide 14 on the reflection side of the linear light guide 14. As the reflection means 24, an aluminum holder or the like that covers at least the reflection side of the linear light guide 14 can be used.
[0130]
In the first to fifth embodiments, the reflective coating film 20 is formed on the reflection side of the linear light guide 14 to prevent light from leaking to the outside from the reflection side of the linear light guide 14. However, in this embodiment, the light leaking from the reflection side of the linear light guide 14 is returned into the linear light guide 14 by the reflecting means 24 provided separately from the linear light guide 14. ing.
[0131]
Even when the reflection means 24 is provided instead of the reflective coating film 20 in this way, light leaking from the reflection side of the linear light guide 14 can be returned into the linear light guide 14, so that illumination is possible. Can be prevented from becoming dark as a whole.
[0132]
Thus, it is not always necessary to form the reflective coating film 20 on the reflection side of the linear light guide 14, and the reflection means 24 may be provided separately from the linear light guide 14 as in this embodiment. .
[0133]
[Seventh Embodiment]
A lighting device according to a seventh embodiment of the present invention will be described with reference to FIG. FIG. 20 is a perspective view showing the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to sixth embodiments shown in FIGS. 1 to 19 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0134]
The illumination device according to the present embodiment is mainly characterized in that the light reflecting portion 20j extends obliquely with respect to the longitudinal direction of the linear light guide 14.
[0135]
In the illuminating device according to the first to sixth embodiments, the light reflecting portion 20 extends in the vertical direction with respect to the longitudinal direction of the linear light guide 14, but in this embodiment, the linear light guide. The light reflecting portion 20 i extends obliquely with respect to the longitudinal direction of 14.
[0136]
According to the present embodiment, since the light reflecting portion 20i extends obliquely with respect to the longitudinal direction of the linear light guide 14, the light intensity distribution can be made more uniform.
[0137]
[Eighth Embodiment]
A lighting apparatus according to an eighth embodiment of the present invention will be described with reference to FIG. FIG. 21 is a plan view showing the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to seventh embodiments shown in FIGS. 1 to 20 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0138]
The illuminating device according to the present embodiment is mainly characterized in that the reflection side of the linear light guide 14a, that is, the surface side on which the light reflecting portion 20 is formed is curved.
[0139]
In the illuminating device according to the first to seventh embodiments, in the light reflecting unit 20 at a position away from the LEDs 12a and 12b, the light incident may be prevented by the other light reflecting unit 20.
[0140]
On the other hand, according to this embodiment, since the reflection side of the linear light guide 14a is curved, even if it is the light reflection part 20 at a position away from the LEDs 12a, 12b, Light is incident without interruption. Therefore, according to the present embodiment, it is possible to provide an illumination device that can obtain a more uniform light intensity distribution.
[0141]
[Ninth Embodiment]
An illumination device according to a ninth embodiment of the present invention will be described with reference to FIG. FIG. 22 is a plan view showing the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to eighth embodiments shown in FIGS. 1 to 21 are denoted by the same reference numerals, and description thereof will be omitted or simplified.
[0142]
In the illumination device according to the present embodiment, the width of the surface of the light reflecting portion 20 increases as the distance from the LEDs 12a and 12b increases, that is, the groove that forms the light reflecting portion 20 as the distance from the LEDs 12a and 12b increases. The main feature is that it is deeper.
[0143]
As shown in FIG. 22, in the illuminating device according to the present embodiment, the depth of the groove forming the light reflecting portion 20 is d near the LEDs 12a and 12b. ₁ As the distance from the LEDs 12a and 12b increases, the depth of the groove constituting the light reflecting portion 20 increases. At the center of the linear light guide 14a, the depth of the groove constituting the light reflecting portion 20 is d. ₁ Deeper d ₂ Is set to
[0144]
In the illuminating device according to the first to seventh embodiments, in the light reflecting unit 20 at a position away from the LEDs 12a and 12b, the light incident may be prevented by the other light reflecting unit 20.
[0145]
On the other hand, according to the present embodiment, the width of the surface of the light reflecting portion 20 gradually increases as the distance from the LEDs 12a and 12b increases, so the light reflecting portion 20 at a position away from the LEDs 12a and 12b. Even if it exists, light is incident without being obstructed by the other light reflecting portions 20.
[0146]
[Tenth embodiment]
A lighting apparatus according to a tenth embodiment of the present invention will be described with reference to FIG. FIG. 23 is a perspective view showing the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to ninth embodiments shown in FIGS. 1 to 22 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0147]
In the illuminating device according to the present embodiment, the region on the reflection side of the linear light guide 14 is divided into two stages in the vertical direction, that is, in the direction perpendicular to the longitudinal direction. An inclination angle of 20k is θ ₀ And the inclination angle of the light reflecting portion 22l is θ in the lower region 22g. ₁ The main feature is that they are equally set.
[0148]
In the lighting device according to the fourth embodiment or the fifth embodiment, the linear light guide 14 is divided into a plurality of regions in the longitudinal direction. However, in this embodiment, the linear light guide 14 is in the vertical direction, that is, And divided into a plurality of regions in a direction perpendicular to the longitudinal direction.
[0149]
In this way, the linear light guide is divided into a plurality of regions in the vertical direction, and the light intensity distribution is made uniform even when the inclination angles of the light reflecting portions are uniformly set within the divided regions. be able to.
[0150]
[Eleventh embodiment]
An illumination device according to an eleventh embodiment of the present invention will be described with reference to FIGS. FIG. 24 is a perspective view showing the lighting apparatus according to the present embodiment. FIG. 25 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment. The same components as those of the illumination devices according to the first to tenth embodiments shown in FIGS. 1 to 23 are denoted by the same reference numerals, and description thereof is omitted or simplified.
[0151]
In the illuminating device according to the present embodiment, the V-shaped grooves forming the light reflecting portions 20m and 20n are equal to each other, and the light reflecting portion 20m provided on the left side of the sheet from the center of the linear light guide 14 is used. Is an inclination angle θ of the left surface of the light reflecting portion 20m so that light introduced from the LED 12a provided on the left side of the paper is emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14. _L (N) is set, and with respect to the light reflecting portion 20n provided on the right side of the sheet from the center of the linear light guide 14, the light introduced from the LED 12b provided on the right side of the sheet is the linear light guide. Inclination angle θ of the right surface of the light reflecting portion 20n so that the light is emitted in a direction perpendicular to the longitudinal direction of 14 _R The main feature is that (n) is set.
[0152]
In addition, although many light reflection parts 20m and 20n are each formed in the reflective side of the linear light guide 14, it is abbreviate | omitted in FIG.
[0153]
As shown in FIG. 24, with respect to the light reflecting portion 20m provided on the left side of the drawing from the center of the linear light guide 14, the light introduced from the LED 12a provided on the left side of the drawing is transmitted to the left side of the light reflecting portion 20m. The angle of inclination θ of the left surface of the light reflecting portion 20m so that the light is reflected by the surface of the light guide and emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14. _L (N) is set.
[0154]
Inclination angle θ of the left surface of the light reflecting portion 20m _L (N) may be set based on, for example, the above-described formula (2) or formula (4). In this case, the end surface on the left side of the sheet of the linear light guide 14 is a reference for the distance X (n).
[0155]
On the other hand, for the light reflecting portion 20n provided on the right side of the drawing from the center of the linear light guide 14, the light introduced from the LED 12b provided on the right side of the drawing is reflected on the right side of the light reflecting portion 20n. Thus, the inclination angle θ of the right surface of the light reflecting portion 20n so that the light is emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14. _R (N) is set.
[0156]
Inclination angle θ of the right surface of the light reflecting portion 20n _R (N) may be set based on, for example, the above-described formula (2) or formula (4). In this case, the end surface on the right side of the sheet of the linear light guide 14 serves as a reference for the distance X (n).
[0157]
Intersection angle θ of the surfaces of the V-shaped grooves constituting the light reflecting portions 20m and 20n _p Are all at equal angles.
[0158]
In the present embodiment, the intersection angle θ of the surface of the V-shaped groove constituting the light reflecting portion. _p Are equal to each other, the inclination angle of the right surface of the light reflecting portion 20m is 180 degrees from the inclination angle θ. _L (N) and intersection angle θ _p The angle is obtained by subtracting. For this reason, the light introduced from the LED 12b to the right side surface of the light reflecting portion 20m is not necessarily emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14.
[0159]
However, the light introduced from the LED 12b is reflected by the surface on the right side of the light reflecting portion 20n and emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14, so that the special problem is Absent.
[0160]
In the present embodiment, the intersection angle θ of the surface of the V-shaped groove constituting the light reflecting portion _p Are set to the same angle, the inclination angle of the left surface of the light reflecting portion 20n is 180 degrees from the inclination angle θ. _R (N) and intersection angle θ _p The angle is obtained by subtracting. For this reason, the light introduced from the LED 12 a to the left side surface of the light reflecting portion 20 n is not necessarily emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14.
[0161]
However, since the light introduced from the LED 12a is reflected by the left surface of the light reflecting portion 20m and is emitted in a direction perpendicular to the longitudinal direction of the linear light guide 14, there is a special problem. Absent.
[0162]
Next, an example of the set value of the tilt angle of the surface of the light reflecting portion of the lighting apparatus according to the present embodiment will be described with reference to FIG. FIG. 25 is a graph showing an example of the inclination angle of the light reflecting portion obtained based on the above formula. The horizontal axis indicates the distance X (n) from the end surface of the linear light guide to the light reflecting portion, and the vertical axis indicates the inclination angle of the surface of the light reflecting portion.
[0163]
In this embodiment, the screen size is 2 inches, the width of the display screen is 35 mm, the number of the light reflecting portions 20 is 170, the pitch of the light reflecting portions 20 is 0.21 mm, and the thickness of the linear light guide 14 is t is 3 mm, the length L of the linear light guide 14 is 37 mm, the distance ΔL between the LEDs 12a and 12b and the linear light guide 14 is 0 mm, the refractive index of the linear light guide 14 is 1.51, The distance between the human eye to be viewed and the display screen was calculated as 350 mm.
[0164]
According to the present embodiment, since the V-shaped grooves forming the light reflecting portions 20m and 20n are equal in shape, the cutting tool used when producing a mold or the like for molding the linear light guide 14 is provided. One type is enough. According to the present embodiment, a mold or the like for molding the linear light guide 14 can be manufactured at low cost, and therefore an illumination device that can make the light intensity distribution uniform can be provided at low cost.
[0165]
[Twelfth embodiment]
A liquid crystal display according to the twelfth embodiment of the present invention will be described with reference to FIG. FIG. 26 is a perspective view of the liquid crystal display device according to the present embodiment. The same components as those of the illumination devices according to the first to eleventh embodiments shown in FIGS. 1 to 25 are denoted by the same reference numerals, and description thereof will be omitted or simplified.
[0166]
The liquid crystal display device according to the present embodiment is configured by combining the illumination device according to any one of the first to eleventh embodiments and a reflective liquid crystal panel.
[0167]
As shown in FIG. 26, the illumination device 10 according to any one of the first to eleventh embodiments is provided on the reflective liquid crystal panel 26.
[0168]
The light emitted from the linear light guide 14 of the illumination device 10 enters the reflective liquid crystal panel 26 via the planar light guide 16 and is a mirror (not shown) provided on the reflective liquid crystal panel 26. And is visually recognized by human eyes. In the present embodiment, the lighting device 10 functions as a front light.
[0169]
According to this embodiment, since the illumination apparatus according to any one of the first to eleventh embodiments is used, the reflective liquid crystal panel can be illuminated with uniform light intensity. Therefore, according to this embodiment, it is possible to provide a liquid crystal display device with good display characteristics.
[0170]
[Thirteenth embodiment]
A liquid crystal display according to a thirteenth embodiment of the present invention is described with reference to FIG. FIG. 27 is a perspective view of the liquid crystal display device according to the present embodiment. The same components as those of the illumination devices according to the first to twelfth embodiments shown in FIGS. 1 to 26 are denoted by the same reference numerals, and description thereof will be omitted or simplified.
[0171]
The liquid crystal display device according to the present embodiment is configured by combining any of the illumination devices of the first to eleventh embodiments and a transmissive liquid crystal panel.
[0172]
As shown in FIG. 27, a transmissive liquid crystal panel 28 is provided on the illumination device 10 according to any one of the first to eleventh embodiments.
[0173]
The light emitted from the linear light guide 14 is incident on the transmissive liquid crystal panel 28 via the planar light guide 16, passes through the transmissive liquid crystal panel 28, and is visually recognized by human eyes.
[0174]
Thus, according to the present embodiment, a liquid crystal display device with good display characteristics can be provided even when a transmissive liquid crystal panel is used.
[0175]
[Modified Embodiment]
The present invention is not limited to the above embodiment, and various modifications can be made.
[0176]
For example, in the tenth embodiment, the linear light guide is divided into two regions in the vertical direction, that is, the direction perpendicular to the longitudinal direction, but may be divided into more regions. Thereby, the light intensity distribution can be made more uniform. However, as the number of sections increases, the number of angles set for the light reflecting portion also increases, so that the appropriate uniformity of the required light intensity distribution and the allowable cost are comprehensively taken into consideration. It is desirable to set the number of categories.
[0177]
(Supplementary note 1) A light source that emits light, and a line that reflects light introduced from the light source by a plurality of light reflecting portions formed on the reflection side, and emits light in a linear form from the emission side facing the reflection side A lighting device having a light guide, wherein the surfaces of the plurality of light reflecting portions are inclined at angles that allow light to converge in the eyes of a viewer. apparatus.
[0178]
(Supplementary Note 2) A light source that emits light, and a line that reflects light introduced from the light source by a plurality of light reflecting portions formed on the reflection side, and emits light in a linear form from the emission side facing the reflection side An illumination device having a light guide, wherein the light reflecting surfaces are at angles such that light is emitted in a direction substantially perpendicular to the longitudinal direction of the linear light guide, A lighting device characterized by being inclined.
[0179]
(Additional remark 3) In the illuminating device according to Additional remark 1 or 2, the plurality of light reflecting portions are V-shaped grooves having the same shape, one surface of which is the surface of the light reflecting portion. Lighting device.
[0180]
(Additional remark 4) In the illuminating device of Additional remark 1 or 2, the said linear light guide is divided into the some area | region in the longitudinal direction, The surface of these light reflection parts is in the divided | segmented area | region. The illumination device is inclined at an equal angle.
[0181]
(Additional remark 5) In the illuminating device according to additional remark 4, in the region including the center of the linear light guide and in the region near the end of the linear light guide, the plurality of light reflecting portions The lighting device characterized in that the surfaces are inclined at an equal angle to each other.
[0182]
(Supplementary note 6) In the illumination device according to supplementary note 4, in the first region divided in the longitudinal direction of the linear light guide, the surface of the light reflecting portion is equally inclined at a first angle, In a second region adjacent to the first region, the surface of the light reflecting portion is equally inclined at a second angle different from the first angle, and the first region, the second region, In the region in the vicinity of the boundary, the light reflecting portion whose surface is inclined at the first angle and the light reflecting portion whose surface is inclined at the second angle are mixed. A lighting device characterized by that.
[0183]
(Supplementary note 7) In the illumination device according to supplementary note 1 or 2, the linear light guide is divided into a plurality of regions in a direction perpendicular to a longitudinal direction, and the plurality of light reflections in the divided regions. The lighting device is characterized in that the surface of the part is inclined at an equal angle.
[0184]
(Supplementary note 8) The illumination device according to supplementary note 1 or 2, wherein the light reflecting portion extends obliquely with respect to a longitudinal direction of the linear light guide.
[0185]
(Supplementary note 9) In the illumination device according to supplementary note 1, the surfaces of the plurality of light reflecting portions are inclined at angles such that light emitted from substantially the center of the light source is converged on the eyes of a viewer. A lighting device characterized by comprising:
[0186]
(Supplementary note 10) In the illumination device according to supplementary note 2, the surface of the plurality of light reflecting portions emits light emitted from substantially the center of the light source in a direction substantially perpendicular to a longitudinal direction of the linear light guide. The lighting device is characterized by being inclined at an angle as described above.
[0187]
(Supplementary Note 11) In the illumination device according to any one of Supplementary Notes 1 to 10, a planar shape that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape. An illumination device further comprising a light guide.
[0188]
(Additional remark 12) The illuminating device in any one of Additional remarks 1 thru | or 11 WHEREIN: The said reflective side is curving the said linear light guide, The illuminating device characterized by the above-mentioned.
[0189]
(Supplementary note 13) In the illumination device according to any one of Supplementary notes 1 to 12, the width of the surface of one of the light reflecting portions and the width of the surface of the other light reflecting portion are different from each other. Lighting device.
[0190]
(Supplementary note 14) The illumination device according to any one of supplementary notes 1 to 13, wherein a reflective coating film is further formed on the reflective side of the linear light guide.
[0191]
(Supplementary Note 15) In the illumination device according to any one of Supplementary Notes 1 to 13, a reflection unit is further provided separately from the linear light guide on the reflection side of the linear light guide. A lighting device.
[0192]
(Supplementary note 16) The illumination device according to any one of supplementary notes 1 to 15, wherein the linear light guide is formed in a substantially quadrangular prism shape.
[0193]
(Supplementary Note 17) A light source that emits light, and a line that reflects light introduced from the light source by a plurality of light reflecting portions formed on the reflection side, and emits light in a linear form from the emission side facing the reflection side A lighting device having a planar light guide, and a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape, and the illumination A liquid crystal display device having a liquid crystal panel illuminated by the device, wherein the surfaces of the plurality of light reflecting portions are each inclined at an angle such that light is converged on the eyes of a viewer. A characteristic liquid crystal display device.
[0194]
(Supplementary Note 18) A light source that emits light and a line that reflects light introduced from the light source by a plurality of light reflecting portions formed on the reflection side and emits light in a linear form from the emission side facing the reflection side An illumination device comprising: a planar light guide; and a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape; and A liquid crystal display device having a liquid crystal panel illuminated by the device, wherein light is emitted from a surface of the plurality of light reflecting portions in a direction substantially perpendicular to a longitudinal direction of the linear light guide. A liquid crystal display device characterized by being inclined at various angles.
[0195]
【The invention's effect】
As described above, according to the present invention, since the angle of the light reflecting portion is set so that the emission angle of light emitted from the linear light guide becomes a desired angle, illumination is performed with uniform light intensity. Can be provided. And using such an illuminating device, a liquid crystal display device with favorable display characteristics can be provided.
[Brief description of the drawings]
1A and 1B are a perspective view and a plan view showing a lighting device according to a first embodiment of the present invention.
FIG. 2 is a plan view showing the lighting apparatus according to the first embodiment of the present invention.
FIG. 3 is a schematic diagram showing a relationship between human eyes and a display screen.
FIG. 4 is a plan view when a refractive index in the air is taken into consideration.
FIG. 5 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the first embodiment of the present invention.
FIG. 6 is a graph showing a light intensity distribution of the lighting apparatus according to the first embodiment of the present invention.
FIG. 7 is a plan view showing a lighting apparatus according to a second embodiment of the present invention.
FIG. 8 is a conceptual diagram showing a relationship between human eyes and a display screen.
FIG. 9 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the illumination apparatus according to the second embodiment of the present invention.
FIG. 10 is a plan view showing an illumination apparatus according to a third embodiment of the present invention.
FIG. 11 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the third embodiment of the present invention.
FIG. 12 is a plan view showing a lighting device according to a fourth embodiment of the present invention.
FIG. 13 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the illumination apparatus according to the fourth embodiment of the present invention.
FIG. 14 is a graph showing a light intensity distribution of the lighting apparatus according to the fourth embodiment of the present invention.
FIG. 15 is a plan view showing a lighting apparatus according to a fifth embodiment of the present invention.
FIG. 16 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the illumination apparatus according to the fifth embodiment of the present invention.
FIG. 17 is a graph showing a light intensity distribution of the lighting apparatus according to the fifth embodiment of the present invention.
FIG. 18 is a plan view showing a lighting apparatus according to a modification of the fifth embodiment of the present invention.
FIG. 19 is a plan view showing a lighting apparatus according to a sixth embodiment of the present invention.
FIG. 20 is a perspective view showing a lighting device according to a seventh embodiment of the present invention.
FIG. 21 is a plan view showing a lighting apparatus according to an eighth embodiment of the present invention.
FIG. 22 is a plan view showing a lighting apparatus according to a ninth embodiment of the present invention.
FIG. 23 is a perspective view showing a lighting apparatus according to a tenth embodiment of the present invention.
FIG. 24 is a perspective view showing a lighting device according to an eleventh embodiment of the present invention.
FIG. 25 is a graph showing an example of the inclination angle of the surface of the light reflecting portion of the lighting apparatus according to the eleventh embodiment of the present invention.
FIG. 26 is a perspective view showing a liquid crystal display device according to a twelfth embodiment of the present invention.
FIG. 27 is a perspective view showing a liquid crystal display according to a thirteenth embodiment of the present invention.
FIG. 28 is a cross-sectional view showing a transmissive liquid crystal panel and a reflective liquid crystal panel.
FIG. 29 is a perspective view showing a proposed lighting device.
FIGS. 30A and 30B are a perspective view and a plan view showing a linear light guide of the proposed lighting device. FIGS.
FIG. 31 is a schematic diagram showing a relationship between human eyes and a display screen.
FIG. 32 is a graph showing the intensity distribution of light emitted from the linear light guide of the proposed lighting device.
FIG. 33 is a plan view showing a proposed lighting device.
[Explanation of symbols]
10 ... Lighting device
12a, 12b ... LED
14 ... Linear light guide
16 ... planar light guide
18 ... Reflective coating film
20, 20a to 20n ... Light reflecting portion
22a-22c ... area
24. Reflecting means
108 ... LCD panel
110 ... Lighting device
112a, 112b ... LED
114 ... Linear light guide
116: planar light guide
118: Reflective coating film
120: Light reflection part
210 ... Glass substrate
212 ... Glass substrate
214 ... Deflector
216 ... Bus line
218 ... Glass substrate
220 ... Liquid crystal
222 ... Glass substrate
224a, 224b, 224c ... color filters
226 ... Glass substrate
228 ... deflector
230 ... Mirror

Claims (4)

A light source that emits light, and a linear light guide that reflects light introduced from the light source by a plurality of light reflecting portions formed on a reflection side, and emits light linearly from an emission side that faces the reflection side And a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape,
Light emitted from the light source is introduced into the linear light guide through an end of the linear light guide,
The surfaces of the plurality of light reflecting portions are respectively at a plurality of different angles according to the positions of the light reflecting portions so that the light emitted from the planar light guide is converged to the eyes of a viewer. Inclined ,
Each of the plurality of light reflecting portions is formed of V-shaped grooves having the same intersection angle.
One surface of the said V-shaped groove | channel is a surface of the said light reflection part, The illuminating device characterized by the above-mentioned . A light source that emits light, and a linear light guide that reflects light introduced from the light source by a plurality of light reflecting portions formed on a reflection side, and emits light linearly from an emission side that faces the reflection side And a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape,
Light emitted from the light source is introduced into the linear light guide through an end of the linear light guide,
The surfaces of the plurality of light reflecting portions are at a plurality of different angles according to the positions of the light reflecting portions so that light is emitted in a direction substantially perpendicular to the longitudinal direction of the linear light guide. It is inclined, respectively,
Each of the plurality of light reflecting portions is formed of V-shaped grooves having the same intersection angle.
One surface of the said V-shaped groove | channel is a surface of the said light reflection part, The illuminating device characterized by the above-mentioned . A light source that emits light, and a linear light guide that reflects light introduced from the light source by a plurality of light reflecting portions formed on a reflection side, and emits light linearly from an emission side that faces the reflection side And a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape, and is illuminated by the illumination device A liquid crystal display device having a liquid crystal panel,
Light emitted from the light source is introduced into the linear light guide through an end of the linear light guide,
The surfaces of the plurality of light reflecting portions are respectively at a plurality of different angles according to the positions of the light reflecting portions so that the light emitted from the planar light guide is converged to the eyes of a viewer. Inclined ,
Each of the plurality of light reflecting portions is formed of V-shaped grooves having the same intersection angle.
One surface of the said V-shaped groove | channel is a surface of the said light reflection part, The liquid crystal display device characterized by the above-mentioned . A light source that emits light, and a linear light guide that reflects light introduced from the light source by a plurality of light reflecting portions formed on a reflection side, and emits light linearly from an emission side that faces the reflection side And a planar light guide that is optically coupled to the linear light guide and emits light introduced from the linear light guide in a planar shape, and is illuminated by the illumination device A liquid crystal display device having a liquid crystal panel,
Light emitted from the light source is introduced into the linear light guide through an end of the linear light guide,
The surfaces of the plurality of light reflecting portions are at a plurality of different angles according to the positions of the light reflecting portions so that light is emitted in a direction substantially perpendicular to the longitudinal direction of the linear light guide. It is inclined, respectively,
Each of the plurality of light reflecting portions is formed of V-shaped grooves having the same intersection angle.
One surface of the said V-shaped groove | channel is a surface of the said light reflection part, The liquid crystal display device characterized by the above-mentioned .

Images